From cf2c9c2d9b250eab9ab2abb2d23862f5ef82eaf7 Mon Sep 17 00:00:00 2001
From: johnnyq <johnny@pittpc.com>
Date: Thu, 5 Nov 2026 12:47:06 -0500
Subject: [PATCH] Let clients pay the card fee - turn on Clients pay the card
 fee on Stripe in Admin > Payment Providers with Stripe's percent and fixed
 rate, and each card payment in the client portal, through an invoice's link,
 by autopay or from Charge Saved Card is grossed up so Stripe's fee comes out
 of it, with one fee per payment shared over its invoices; the fee is shown
 before paying (Pay invoices, checkout, the guest pay page, invoice pages,
 autopay and the Charge Saved Card window) and goes on each invoice as a Card
 Fee line with no tax when the payment is booked, carried in the
 PaymentIntent's itflow_fees metadata and checked against the amount received
 to the cent; a client can be let off it with No card fee on their Billing
 tab, refunding a card payment takes its Card Fee line back off, autopay and
 Charge Saved Card now compare cents instead of whole dollars, database 3.5.6
 adds the provider and client columns, changelog updated

---
 CHANGELOG.md                                  |   9 +-
 admin/database_updates/3.5.6.php              |  33 +++
 .../payment_provider_edit.php                 |  54 +++-
 admin/payment_providers.php                   |  16 +-
 admin/post/payment_provider.php               |   2 +-
 agent/modals/client/client_add.php            |   6 +
 agent/modals/client/client_card_fee_field.php |  30 +++
 agent/modals/client/client_edit.php           |   8 +-
 .../payment/payment_saved_method_add.php      |  19 +-
 agent/post/client.php                         |   4 +-
 agent/post/client_model.php                   |   2 +
 agent/post/payment.php                        |  50 +++-
 agent/recurring_invoice.php                   |   4 +-
 client/invoice.php                            |   8 +-
 client/pay.php                                |  11 +-
 client/post.php                               |   4 +-
 client/recurring_invoice.php                  |   3 +-
 client/saved_payment_methods.php              |   9 +-
 client/unpaid_invoices.php                    |  37 ++-
 cron/nightly_tasks.php                        |  33 ++-
 db.sql                                        |   4 +
 functions/billing_pay.php                     | 233 ++++++++++++++++--
 functions/payment_provider.php                |  44 +++-
 guest/guest_ajax.php                          |  25 +-
 guest/guest_pay_invoice_stripe.php            |  34 ++-
 guest/guest_view_invoice.php                  |   4 +-
 js/portal.js                                  |  23 +-
 27 files changed, 615 insertions(+), 94 deletions(-)
 create mode 100644 admin/database_updates/3.5.6.php
 create mode 100644 agent/modals/client/client_card_fee_field.php

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9dd887c94..64c731141 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@ This file documents all notable changes made to ITFlow.
 
 ### Upgrading
 
-Update from Maintenance > Update — Queue Update hands the job to cron, which updates the files and applies this release's one database change (3.5.4 to 3.5.5) in the same pass. Nothing else is required. Everyone is signed out once after the update, agents and client portal contacts alike - see Security. The new Payment Provider Fees job in Maintenance > Cron is set up by itself.
+Update from Maintenance > Update — Queue Update hands the job to cron, which updates the files and applies this release's two database changes (3.5.4 to 3.5.6) in the same pass. Nothing else is required. Everyone is signed out once after the update, agents and client portal contacts alike - see Security. The new Payment Provider Fees job in Maintenance > Cron is set up by itself.
 
 ### Security
 
@@ -21,6 +21,7 @@ Update from Maintenance > Update — Queue Update hands the job to cron, which u
 - API: products can be updated through the API (`products/update`). Only the fields you send are changed, and the key's user needs edit access to Sales, the same as editing a product in ITFlow.
 - API keys: agents are notified in ITFlow a week before an API key expires, so an integration doesn't stop without warning.
 - Payment Providers: Stripe's fee on a card payment is now recorded as an expense about 15 minutes after the payment, instead of the next morning. A new Payment Provider Fees job in Maintenance > Cron does it, and you can run it more often there. Record fees now still works any time.
+- Payment Providers: clients can pay the card fee. Turn on Clients pay the card fee on Stripe in Admin > Payment Providers and enter what Stripe charges you, as 2.9% plus 0.30. Each card payment is then made bigger by Stripe's fee on it, so you get the full invoice. The fee goes on the invoice as a Card Fee line, with no tax, when the payment goes through. Clients see it before they pay: on Pay invoices and the checkout page in the client portal, on the page an invoice's link opens, and next to autopay. It applies to payments in the client portal, through an invoice's link, by autopay, and when you charge a saved card, where the Charge Saved Card window shows it too. One payment for several invoices has one fee, shared over them. A client can be let off it with No card fee on their Billing tab. Refunding a card payment from ITFlow takes its Card Fee line back off the invoice. It is off until you turn it on. Card surcharges have rules where you and your clients are - in the US, for one, the card networks cap them and don't allow them on debit cards - so check them before turning it on.
 
 ### Bug Fixes
 
@@ -41,6 +42,12 @@ Update from Maintenance > Update — Queue Update hands the job to cron, which u
 - New `requestIsMfaSetup($allowed)` in `functions/auth.php` decides what a session that still has to set up MFA may request: the script really running (`realpath($_SERVER['SCRIPT_FILENAME'])` under the app root, never `PHP_SELF`, which a path added after the script name changes), and every GET and POST key inside one of the shapes allowed for that script. `includes/load_user_session.php` applies it when `user_config_force_mfa` is 1 and `user_token` is empty, allowing `agent/user/mfa_enforcement.php` with no parameters and `agent/user/post.php` with only `csrf_token`, `enable_mfa` and `verify_code`, or `?logout` - everything else redirects to the set up page, modals and AJAX included. The client portal gate in `client/includes/check_login.php` now uses it too (`profile.php?mfa`, and `post.php` with `portal_mfa_enable` or `?logout`), replacing its `basename($_SERVER['PHP_SELF'])` test; the separate gate in `client/post.php`, which let any request through that carried `portal_mfa_enable` or `logout` alongside other actions, is gone. `portalViewAsAccess()` refuses an agent still owing MFA set up. The `enable_mfa` handler sends `userNotifyChange()`.
 - `accountLedgerShows($all_accounts)`: across every account, the `in` and `out` cuts leave out `txn_kind` `transfer_in` and `transfer_out`. `agent/transactions.php` does the same for its Money in and Money out totals, except on the Transfers pill, and notes it in the table footer when the listed lines include transfers the totals leave out. The transactions export, which takes its cuts from the same function, follows.
 - Stripe fees are recorded by a new job, `cron/payment_provider_fees.php` (`payment_provider_fees` in `includes/cron_jobs.php`, every 15 minutes, interval-safe), instead of `cron/nightly_tasks.php`. The dispatcher seeds its row the first time it sees it. `paymentProviderRecordFees()` now holds `GET_LOCK('itflow_payment_provider_fees', 0)` around the work, which moved to `paymentProviderRecordFeesLocked()`, and returns `'busy' => true` when another run has it - "has no fee yet" is read before the fee is written, so two runs at once would each record it. Record fees now says when a run is in progress.
+- Database 3.5.6 adds `payment_providers.payment_provider_card_fee`, `payment_provider_card_fee_percent` (decimal 5,2) and `payment_provider_card_fee_fixed`, and `clients.client_card_fee_exempt`, all defaulting to 0. Like 3.5.4 and 3.5.5 it is safe to run again, and `db.sql` has the columns.
+- The card fee lives in `functions/billing_pay.php`. `billingCardFeeRates()` reads it off the Stripe provider, `billingCardFeeFor($client_id)` adds the client's exemption, and `billingCardFeeCents($cents, $rates)` grosses up in whole numbers: `ceil((cents + fixed) * 10000 / (10000 - percent * 100)) - cents`, so the fee is the percent of everything charged plus the fixed part. `js/portal.js` works it the same way from `data-pay-fee-percent` (hundredths of a percent) and `data-pay-fee-fixed` (cents) on the Pay invoices form. `billingCardFeeShares()` splits one payment's fee over its invoices in proportion, by largest remainder.
+- `billingPaySelection()` now also returns `fees` ([invoice_id => cents]), `fee`, `charge` and `fee_rates`; the card limit is still checked on what the invoices come to, without the fee. `billingStripeIntentParams()` charges the fee and puts it in the PaymentIntent's metadata as `itflow_fees`, in the same `id:cents,...` form as `itflow_invoices`, which still carries what each invoice was owed. The guest Payment Element (`guest/guest_ajax.php`), autopay in `cron/nightly_tasks.php` and Charge Saved Card (`agent/post/payment.php`) add `itflow_fees` for their one invoice.
+- Booking: `billingStripeBook()` checks that `itflow_invoices` and `itflow_fees` add up to `amount_received` and refuses an `itflow_fees` that doesn't read. For each invoice it calls `billingCardFeeAdd($invoice_id, $fee, $date)` before the payment, which inserts a Card Fee line (`BILLING_CARD_FEE_NAME`, no tax, no product) and raises `invoice_amount` by the fee directly rather than through `billingRecalc()`, so the invoice's other lines aren't re-taxed and the payment pays it to the cent. The payment is what was owed plus the fee. A PaymentIntent without `itflow_fees`, from before, books as it did. The guest return, autopay and Charge Saved Card do the same, and now compare the amount received with the balance and fee in whole cents (autopay and Charge Saved Card compared whole dollars with `intval()`).
+- Refunding a Stripe payment (`refund_payment_stripe`) retrieves its PaymentIntent and calls `billingCardFeeRemove($invoice_id, $fee)`, which deletes the latest Card Fee line of that amount and lowers `invoice_amount` to match, before the invoice's status is worked out again.
+- `paymentProviderCheck()` takes `card_fee`, `card_fee_percent` (0 to 15) and `card_fee_fixed` (0 to 100), needs at least one rate above 0 when it is on, and keeps the saved rates when it is off. `paymentProviderChangeLines()` and the Create audit line include it, through the new `paymentProviderCardFeeText()`. The client's switch is `agent/modals/client/client_card_fee_field.php`, shown on the Billing tab of Add and Edit Client while Stripe is set up, and saved through `card_fee_field` and `card_fee_exempt` in `agent/post/client_model.php`.
 
 ## [26.11.2]
 
diff --git a/admin/database_updates/3.5.6.php b/admin/database_updates/3.5.6.php
new file mode 100644
index 000000000..4ad269014
--- /dev/null
+++ b/admin/database_updates/3.5.6.php
@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * ITFlow - Database update to version 3.5.6 (from 3.5.5)
+ * Included by admin/database_updates.php - do not access directly
+ *
+ * Clients can pay the card fee. On the Stripe payment provider:
+ * payment_provider_card_fee turns it on, and payment_provider_card_fee_percent
+ * and payment_provider_card_fee_fixed are what Stripe charges on a card
+ * payment. On a client, client_card_fee_exempt lets them off it. All start
+ * off, so nothing changes until it is turned on.
+ *
+ * Re-runnable: each column is added only where it isn't there yet.
+ */
+
+defined('FROM_DB_UPDATER') || die("Direct file access is not allowed");
+
+    $itflow_new_columns = [
+        ['payment_providers', 'payment_provider_card_fee', "TINYINT(1) NOT NULL DEFAULT 0 AFTER `payment_provider_expense_category`"],
+        ['payment_providers', 'payment_provider_card_fee_percent', "DECIMAL(5,2) NOT NULL DEFAULT 0.00 AFTER `payment_provider_card_fee`"],
+        ['payment_providers', 'payment_provider_card_fee_fixed', "DECIMAL(15,2) NOT NULL DEFAULT 0.00 AFTER `payment_provider_card_fee_percent`"],
+        ['clients', 'client_card_fee_exempt', "TINYINT(1) NOT NULL DEFAULT 0 AFTER `client_tax_exempt_expires`"],
+    ];
+
+    foreach ($itflow_new_columns as [$itflow_table, $itflow_column, $itflow_definition]) {
+        $itflow_column_exists = mysqli_query($mysqli, "SELECT 1 FROM information_schema.COLUMNS
+            WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = '$itflow_table' AND COLUMN_NAME = '$itflow_column' LIMIT 1");
+        if (!$itflow_column_exists || mysqli_num_rows($itflow_column_exists) === 0) {
+            mysqli_query($mysqli, "ALTER TABLE `$itflow_table` ADD `$itflow_column` $itflow_definition");
+        }
+    }
+
+    unset($itflow_new_columns, $itflow_table, $itflow_column, $itflow_definition, $itflow_column_exists);
diff --git a/admin/modals/payment_provider/payment_provider_edit.php b/admin/modals/payment_provider/payment_provider_edit.php
index 888500d1a..ab586ff95 100644
--- a/admin/modals/payment_provider/payment_provider_edit.php
+++ b/admin/modals/payment_provider/payment_provider_edit.php
@@ -4,8 +4,8 @@
  * Admin > Payment Providers - one provider's window: Add (no id, or from
  * payment_provider_add.php) or Edit. Its keys - the secret one never put back
  * into the page, so left empty it stays - whether it is on, the account its
- * payments go into, the card limit, and whether its fees are recorded as
- * expenses. Save asks first (check_payment_provider,
+ * payments go into, the card limit, whether its fees are recorded as
+ * expenses, and whether clients pay a card fee to cover them. Save asks first (check_payment_provider,
  * admin/post/payment_provider.php): what is wrong shows beside each field and
  * the window stays open; once all is right, it saves.
  */
@@ -35,6 +35,9 @@ $vendor_id = intval($row['payment_provider_expense_vendor'] ?? 0);
 $category_id = intval($row['payment_provider_expense_category'] ?? 0);
 $threshold = round(floatval($row['payment_provider_threshold'] ?? 0), 2);
 $records_fees = $row ? ($vendor_id > 0 && $category_id > 0) : true;
+$card_fee = intval($row['payment_provider_card_fee'] ?? 0) === 1;
+$card_fee_percent = round(floatval($row['payment_provider_card_fee_percent'] ?? 0), 2);
+$card_fee_fixed = round(floatval($row['payment_provider_card_fee_fixed'] ?? 0), 2);
 
 // A new one starts on an account and a vendor named for it, and Processing Fee, where there are those
 if (!$row) {
@@ -204,6 +207,38 @@ ob_start();
             </div>
         </div>
 
+        <div class="mb-3">
+            <div class="form-check form-switch">
+                <input type="checkbox" class="form-check-input" name="card_fee" value="1" id="paymentProviderCardFee" <?= $card_fee ? 'checked' : '' ?> data-provider-card-fee-switch>
+                <label class="form-check-label" for="paymentProviderCardFee">Clients pay the card fee</label>
+            </div>
+            <div class="form-text ps-5">Each card payment is made bigger by what <?= escapeHtml($name) ?> takes of it, so you get what the invoice is for. The fee goes on the invoice as a Card Fee line, and clients see it before they pay - in the client portal, through an invoice's link, by autopay, or when you charge a saved card. A client can be let off it on their Billing tab.</div>
+        </div>
+
+        <div data-provider-card-fee>
+            <div class="row">
+                <div class="col-sm-6 mb-3">
+                    <label class="form-label" for="paymentProviderCardFeePercent">Percent</label>
+                    <div class="input-group has-validation">
+                        <span class="input-group-text"><i class="fa fa-fw fa-percent"></i></span>
+                        <input type="text" class="form-control" name="card_fee_percent" id="paymentProviderCardFeePercent" inputmode="decimal" maxlength="5" placeholder="2.9" value="<?= $card_fee_percent > 0 ? escapeHtml(rtrim(rtrim(number_format($card_fee_percent, 2, '.', ''), '0'), '.')) : '' ?>">
+                        <span class="input-group-text">%</span>
+                    </div>
+                    <?= $error_for('card_fee_percent') ?>
+                </div>
+                <div class="col-sm-6 mb-3">
+                    <label class="form-label" for="paymentProviderCardFeeFixed">Plus</label>
+                    <div class="input-group has-validation">
+                        <span class="input-group-text"><i class="fa fa-fw fa-coins"></i></span>
+                        <input type="text" class="form-control" name="card_fee_fixed" id="paymentProviderCardFeeFixed" inputmode="decimal" maxlength="6" placeholder="0.30" value="<?= $card_fee_fixed > 0 ? escapeHtml(number_format($card_fee_fixed, 2, '.', '')) : '' ?>">
+                        <?php if ($currency !== '') { ?><span class="input-group-text"><?= escapeHtml($currency) ?></span><?php } ?>
+                    </div>
+                    <?= $error_for('card_fee_fixed') ?>
+                </div>
+            </div>
+            <div class="form-text mt-n2 mb-3">What <?= escapeHtml($name) ?> charges you on a card payment - your account's rate, as 2.9% plus 0.30. Card surcharges have rules where you and your clients are: in the US, for one, the card networks cap them and don't allow them on debit cards, and some states limit them further.</div>
+        </div>
+
     </div>
     <div class="modal-footer">
         <button type="submit" name="<?= $row ? 'edit_payment_provider' : 'add_payment_provider' ?>" class="btn btn-primary text-bold" data-provider-save <?= !$row && !$free_kinds ? 'disabled' : '' ?>>
@@ -214,7 +249,7 @@ ob_start();
 </form>
 
 <script>
-// Fees - their vendor and category only while they are recorded. Save - asked first, so what is wrong shows here
+// Fees - their vendor and category only while they are recorded, the card fee's rates only while clients pay it. Save - asked first, so what is wrong shows here
 (function () {
     var form = document.querySelector('[data-payment-provider-form]:not([data-ready])');
     if (!form) {
@@ -223,6 +258,8 @@ ob_start();
     form.setAttribute('data-ready', '1');
     var feesSwitch = form.querySelector('[data-provider-fees-switch]');
     var fees = form.querySelector('[data-provider-fees]');
+    var cardFeeSwitch = form.querySelector('[data-provider-card-fee-switch]');
+    var cardFee = form.querySelector('[data-provider-card-fee]');
     var save = form.querySelector('[data-provider-save]');
     var accountNote = form.querySelector('[data-provider-account]');
     var checked = false;
@@ -238,6 +275,17 @@ ob_start();
     feesSwitch.addEventListener('change', showFees);
     showFees();
 
+    // The card fee's rates only while clients pay it - off, they aren't sent and stay as saved
+    function showCardFee() {
+        var on = cardFeeSwitch.checked;
+        cardFee.classList.toggle('opacity-50', !on);
+        cardFee.querySelectorAll('input').forEach(function (el) {
+            el.disabled = !on;
+        });
+    }
+    cardFeeSwitch.addEventListener('change', showCardFee);
+    showCardFee();
+
     function clearErrors() {
         form.querySelectorAll('.is-invalid').forEach(function (el) { el.classList.remove('is-invalid'); });
         form.querySelectorAll('[data-error-for]').forEach(function (el) {
diff --git a/admin/payment_providers.php b/admin/payment_providers.php
index f93a31bc9..0aef3448f 100644
--- a/admin/payment_providers.php
+++ b/admin/payment_providers.php
@@ -5,12 +5,12 @@
  * through (functions/payment_provider.php). Each row says whether it is on,
  * live or test (as its keys say), the account its payments go into, its card
  * limit, whether its fees are recorded as expenses (and what they came to,
- * and how many are still to record), its saved cards and the autopay on
- * them, and its card payments in the last 30 days. Check connection asks
- * the provider whose account the key is; Record fees now does what the
- * Payment Provider Fees job does every few minutes. Add and Edit are one window
- * (modals/payment_provider/payment_provider_edit.php); the rest are
- * admin/post/payment_provider.php.
+ * and how many are still to record) and the card fee clients pay, its saved
+ * cards and the autopay on them, and its card payments in the last 30 days.
+ * Check connection asks the provider whose account the key is; Record fees
+ * now does what the Payment Provider Fees job does every few minutes. Add
+ * and Edit are one window (modals/payment_provider/payment_provider_edit.php);
+ * the rest are admin/post/payment_provider.php.
  */
 
 // Default Column Sortby Filter
@@ -33,6 +33,7 @@ if (!isset($sortable_columns[$sort])) {
 
 $sql = mysqli_query($mysqli, "SELECT SQL_CALC_FOUND_ROWS payment_provider_id, payment_provider_name, payment_provider_description, payment_provider_private_key,
         payment_provider_threshold, payment_provider_active, payment_provider_account, payment_provider_expense_vendor, payment_provider_expense_category,
+        payment_provider_card_fee, payment_provider_card_fee_percent, payment_provider_card_fee_fixed,
         account_name, account_archived_at, vendor_name, category_name,
         COALESCE(cards.saved_cards, 0) AS saved_cards, COALESCE(cards.autopay, 0) AS autopay,
         (SELECT MAX(payment_date) FROM payments WHERE payment_archived_at IS NULL AND payment_reference LIKE CONCAT(payment_provider_name, ' - %')) AS last_paid
@@ -160,6 +161,9 @@ $csrf = $_SESSION['csrf_token'];
                         <?php } else { ?>
                             <span class="text-body-secondary">Not recorded</span>
                         <?php } ?>
+                        <?php if (billingCardFeeRates($row)) { ?>
+                            <div class="mt-1" data-provider-card-fee title="Clients pay it on each card payment, as a Card Fee line on the invoice"><i class="fas fa-fw fa-hand-holding-usd text-secondary me-1"></i>Clients pay <?= escapeHtml(paymentProviderCardFeeText($row)) ?></div>
+                        <?php } ?>
                     </td>
                     <td class="d-none d-md-table-cell small text-nowrap">
                         <?php if ($cards) { ?>
diff --git a/admin/post/payment_provider.php b/admin/post/payment_provider.php
index 9be19fc13..68a8845ef 100644
--- a/admin/post/payment_provider.php
+++ b/admin/post/payment_provider.php
@@ -70,7 +70,7 @@ if (isset($_POST['check_payment_provider']) || isset($_POST['add_payment_provide
         $provider_id = paymentProviderWrite($after);
         $account_name = (string) (paymentProviderRow($provider_id)['account_name'] ?? '');
         logAudit("Payment Provider", "Create", "$session_name added payment provider " . escapeSql("$name ($mode mode), payments into $account_name, card limit " . paymentProviderLimitText($after['payment_provider_threshold'])
-            . ', fees ' . ($after['payment_provider_expense_vendor'] ? 'recorded' : 'not recorded')), 0, $provider_id);
+            . ', fees ' . ($after['payment_provider_expense_vendor'] ? 'recorded' : 'not recorded') . ', card fee clients pay ' . paymentProviderCardFeeText($after)), 0, $provider_id);
         flashAlert('<strong>' . escapeHtml($name) . '</strong> added - clients can pay invoices by card' . ($mode === 'test' ? '. Its keys are test keys, so no real money moves until they are live ones' : ''));
         redirect();
     }
diff --git a/agent/modals/client/client_add.php b/agent/modals/client/client_add.php
index 92223bb6c..4e971ef73 100644
--- a/agent/modals/client/client_add.php
+++ b/agent/modals/client/client_add.php
@@ -275,6 +275,12 @@ ob_start();
                         <small class="text-secondary">Emailed as set in Invoice Settings. Off, this client gets neither - invoices can still be sent by hand.</small>
                     </div>
 
+                    <?php
+                    $client_card_fee_exempt = false;
+                    $client_card_fee_key = 'New';
+                    require __DIR__ . '/client_card_fee_field.php';
+                    ?>
+
 
                 </div>
 
diff --git a/agent/modals/client/client_card_fee_field.php b/agent/modals/client/client_card_fee_field.php
new file mode 100644
index 000000000..b35259ce3
--- /dev/null
+++ b/agent/modals/client/client_card_fee_field.php
@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * Letting a client off the card fee - on the Billing tab of client_add.php and
+ * client_edit.php, while Stripe takes card payments. They set
+ * $client_card_fee_exempt (bool) and $client_card_fee_key (keeps ids apart).
+ * Saved by agent/post/client.php as client_card_fee_exempt; the fee itself is
+ * set on Stripe in Admin > Payment Providers (functions/billing_pay.php).
+ */
+
+isset($mysqli) || die("Direct file access is not allowed");
+
+if (billingStripeProvider()) {
+    $ccf_rates = billingCardFeeRates();
+    $ccf_key = $client_card_fee_key ?? 'New';
+    ?>
+    <div class="mb-3">
+        <input type="hidden" name="card_fee_field" value="1">
+        <div class="form-check form-switch">
+            <input type="checkbox" class="form-check-input" name="card_fee_exempt" value="1" id="clientCardFeeExempt<?= escapeHtml($ccf_key) ?>"<?= !empty($client_card_fee_exempt) ? ' checked' : '' ?>>
+            <label class="form-check-label" for="clientCardFeeExempt<?= escapeHtml($ccf_key) ?>">No card fee</label>
+        </div>
+        <small class="text-secondary">
+            <?= $ccf_rates
+                ? 'Clients pay a ' . escapeHtml(billingCardFeeText($ccf_rates)) . ' card fee when they pay by card - this one doesn\'t.'
+                : 'Clients don\'t pay a card fee now - if they are set to in Admin > Payment Providers, this one won\'t.' ?>
+        </small>
+    </div>
+    <?php
+}
diff --git a/agent/modals/client/client_edit.php b/agent/modals/client/client_edit.php
index 960ce5d91..69a69659c 100644
--- a/agent/modals/client/client_edit.php
+++ b/agent/modals/client/client_edit.php
@@ -10,7 +10,7 @@ enforceClientAccess();
 
 $sql = mysqli_query($mysqli, "SELECT client_abbreviation, client_archived_at, client_created_at, client_lead, client_name,
     client_notes, client_reminders, client_referral, client_tax_id_number,
-    client_default_tax_id, client_tax_exempt, client_tax_exempt_number, client_tax_exempt_expires,
+    client_default_tax_id, client_tax_exempt, client_tax_exempt_number, client_tax_exempt_expires, client_card_fee_exempt,
     client_type, client_website FROM clients WHERE client_id = $client_id LIMIT 1");
 
 $row = mysqli_fetch_assoc($sql);
@@ -22,6 +22,7 @@ $client_website = escapeHtml($row['client_website']);
 $client_referral = escapeHtml($row['client_referral']);
 $row_referral = (string) $row['client_referral'];
 $client_reminders = intval($row['client_reminders'] ?? 1);
+$client_card_fee_exempt = intval($row['client_card_fee_exempt'] ?? 0) === 1;
 $client_tax_id_number = escapeHtml($row['client_tax_id_number']);
 $client_abbreviation = escapeHtml($row['client_abbreviation']);
 $client_notes = escapeHtml($row['client_notes']);
@@ -168,6 +169,11 @@ ob_start();
                         <small class="text-secondary">Emailed as set in Invoice Settings. Off, this client gets neither - invoices can still be sent by hand.</small>
                     </div>
 
+                    <?php
+                    $client_card_fee_key = $client_id;
+                    require __DIR__ . '/client_card_fee_field.php';
+                    ?>
+
 
                 </div>
 
diff --git a/agent/modals/payment/payment_saved_method_add.php b/agent/modals/payment/payment_saved_method_add.php
index a838ac96b..c1f6f4db9 100644
--- a/agent/modals/payment/payment_saved_method_add.php
+++ b/agent/modals/payment/payment_saved_method_add.php
@@ -2,7 +2,8 @@
 
 /*
  * Charge a card the client saved - the invoice's balance, through the
- * provider the card is with. ?id= (the invoice)
+ * provider the card is with, and the card fee when the client pays it
+ * (functions/billing_pay.php). ?id= (the invoice)
  */
 
 require_once '../../../includes/modal_header.php';
@@ -29,6 +30,13 @@ if (!$cards) {
     exit(json_encode(['error' => $invoice['client_name'] . ' has no card on file with a payment provider that is turned on.']));
 }
 
+// What is charged - agent/post/payment.php works it out the same way
+$currency = (string) $invoice['invoice_currency_code'];
+$fee_rates = billingCardFeeFor($client_id);
+$invoice_cents = (int) round(floatval($invoice['invoice_amount']) * 100);
+$fee = billingCardFeeCents($invoice_cents, $fee_rates) / 100;
+$charge = $invoice_cents / 100 + $fee;
+
 ob_start();
 
 ?>
@@ -43,7 +51,12 @@ ob_start();
     <div class="modal-body">
         <div class="text-center p-3 mb-3 rounded bg-body-tertiary">
             <div class="itflow-billing-stat-label">Charging</div>
-            <div class="itflow-billing-stat-value"><?= escapeHtml(billingMoney($invoice['invoice_amount'], $invoice['invoice_currency_code'])) ?></div>
+            <div class="itflow-billing-stat-value"><?= escapeHtml(billingMoney($charge, $currency)) ?></div>
+            <?php if ($fee > 0) { ?>
+                <div class="small text-body-secondary" title="<?= escapeHtml(billingCardFeeTerms($fee_rates, $currency)) ?>">
+                    <?= escapeHtml(billingMoney($invoice['invoice_amount'], $currency)) ?> and a <?= escapeHtml(billingMoney($fee, $currency)) ?> card fee, which goes on the invoice
+                </div>
+            <?php } ?>
         </div>
         <label class="form-label">Card <strong class="text-danger">*</strong></label>
         <div class="input-group">
@@ -58,7 +71,7 @@ ob_start();
     </div>
     <div class="modal-footer">
         <button type="submit" name="add_payment_stripe" class="btn btn-success text-bold confirm-link" data-confirm-title="Charge the card?"
-            data-confirm-text="<?= escapeHtml(billingMoney($invoice['invoice_amount'], $invoice['invoice_currency_code'])) ?> is taken from the card now." data-confirm-button="Charge">
+            data-confirm-text="<?= escapeHtml(billingMoney($charge, $currency)) ?> is taken from the card now<?= $fee > 0 ? ', with its ' . escapeHtml(billingMoney($fee, $currency)) . ' card fee' : '' ?>." data-confirm-button="Charge">
             <i class="fas fa-bolt me-2"></i>Charge
         </button>
         <button type="button" class="btn btn-light" data-bs-dismiss="modal"><i class="fas fa-times me-2"></i>Cancel</button>
diff --git a/agent/post/client.php b/agent/post/client.php
index 4998b4d21..f27c49b0d 100644
--- a/agent/post/client.php
+++ b/agent/post/client.php
@@ -45,7 +45,7 @@ if (isset($_POST['add_client'])) {
     $referral = escapeSql(categoryEnsure('Referral', $_POST['referral'] ?? ''));
 
     // Create client
-    mysqli_query($mysqli, "INSERT INTO clients SET client_name = '$name', client_type = '$type', client_website = '$website', client_referral = '$referral', client_currency_code = '$session_company_currency', client_reminders = " . ($reminders ?? 1) . ", client_tax_id_number = '$tax_id_number', client_lead = $lead, client_abbreviation = '$abbreviation', client_notes = '$notes', client_accessed_at = NOW()" . ($tax_input !== null ? ", " . taxClientSetSql($tax_input) : '') . billingClientLegacySql());
+    mysqli_query($mysqli, "INSERT INTO clients SET client_name = '$name', client_type = '$type', client_website = '$website', client_referral = '$referral', client_currency_code = '$session_company_currency', client_reminders = " . ($reminders ?? 1) . ", client_card_fee_exempt = " . ($card_fee_exempt ?? 0) . ", client_tax_id_number = '$tax_id_number', client_lead = $lead, client_abbreviation = '$abbreviation', client_notes = '$notes', client_accessed_at = NOW()" . ($tax_input !== null ? ", " . taxClientSetSql($tax_input) : '') . billingClientLegacySql());
 
     $client_id = mysqli_insert_id($mysqli);
 
@@ -125,7 +125,7 @@ if (isset($_POST['edit_client'])) {
     $referral = escapeSql(categoryEnsure('Referral', $_POST['referral'] ?? ''));
 
     // Update client
-    mysqli_query($mysqli, "UPDATE clients SET client_name = '$name', client_type = '$type', client_website = '$website', client_referral = '$referral'" . ($reminders !== null ? ", client_reminders = $reminders" : '') . ", client_tax_id_number = '$tax_id_number', client_lead = $lead, client_abbreviation = '$abbreviation', client_notes = '$notes'$tax_set_sql WHERE client_id = $client_id");
+    mysqli_query($mysqli, "UPDATE clients SET client_name = '$name', client_type = '$type', client_website = '$website', client_referral = '$referral'" . ($reminders !== null ? ", client_reminders = $reminders" : '') . ($card_fee_exempt !== null ? ", client_card_fee_exempt = $card_fee_exempt" : '') . ", client_tax_id_number = '$tax_id_number', client_lead = $lead, client_abbreviation = '$abbreviation', client_notes = '$notes'$tax_set_sql WHERE client_id = $client_id");
 
     // Tags - client tags only, and an admin can type a new one in (functions/tags.php)
     tagSetForRecord('client', $client_id, (array) ($_POST['tags'] ?? []));
diff --git a/agent/post/client_model.php b/agent/post/client_model.php
index 8070711f0..538cf5f45 100644
--- a/agent/post/client_model.php
+++ b/agent/post/client_model.php
@@ -13,6 +13,8 @@ $notes = escapeSql($_POST['notes'] ?? '');
 $lead = intval($_POST['lead'] ?? 0);
 // Reminders and statements - only when the Billing tab was on the form
 $reminders = isset($_POST['reminders_field']) ? intval(!empty($_POST['reminders'])) : null;
+// No card fee - only when the Billing tab had it (agent/modals/client/client_card_fee_field.php)
+$card_fee_exempt = isset($_POST['card_fee_field']) ? intval(!empty($_POST['card_fee_exempt'])) : null;
 // Its tax rate and exemption - only when the Billing tab was on the form;
 // client.php adds the client's row when editing (taxClientSetSql())
 $tax_input = isset($_POST['tax_fields']) ? [
diff --git a/agent/post/payment.php b/agent/post/payment.php
index 699b78af0..57d3c8bc2 100644
--- a/agent/post/payment.php
+++ b/agent/post/payment.php
@@ -320,24 +320,32 @@ if (isset($_POST['add_payment_stripe'])) {
     $stripe = new \Stripe\StripeClient($private_key);
 
     $balance_to_pay = round($invoice_amount, 2);
-    $pi_description = "ITFlow: $client_name payment of $invoice_currency_code $balance_to_pay for $invoice_prefix$invoice_number";
+    // The card fee, when the client pays it - as the Charge Saved Card window showed it (functions/billing_pay.php)
+    $balance_cents = (int) round($balance_to_pay * 100);
+    $fee_cents = billingCardFeeCents($balance_cents, billingCardFeeFor($client_id));
+    $pi_metadata = [
+        'itflow_client_id' => $client_id,
+        'itflow_client_name' => $client_name,
+        'itflow_invoice_number' => $invoice_prefix . $invoice_number,
+        'itflow_invoice_id' => $invoice_id,
+    ];
+    if ($fee_cents > 0) {
+        $pi_metadata['itflow_fees'] = "$invoice_id:$fee_cents";
+    }
+    $pi_description = "ITFlow: $client_name payment of $invoice_currency_code " . number_format(($balance_cents + $fee_cents) / 100, 2, '.', '')
+        . ($fee_cents > 0 ? ' (with a ' . number_format($fee_cents / 100, 2, '.', '') . ' card fee)' : '') . " for $invoice_prefix$invoice_number";
 
     // Create a payment intent
     try {
         $payment_intent = $stripe->paymentIntents->create([
-            'amount' => intval(round($balance_to_pay * 100)), // Times by 100 as Stripe expects values in cents
+            'amount' => $balance_cents + $fee_cents, // Stripe expects cents
             'currency' => $invoice_currency_code,
             'customer' => $payment_provider_client,
             'payment_method' => $saved_payment_method,
             'off_session' => true,
             'confirm' => true,
             'description' => $pi_description,
-            'metadata' => [
-                'itflow_client_id' => $client_id,
-                'itflow_client_name' => $client_name,
-                'itflow_invoice_number' => $invoice_prefix . $invoice_number,
-                'itflow_invoice_id' => $invoice_id,
-            ]
+            'metadata' => $pi_metadata,
         ]);
 
         // Get details from PI
@@ -353,14 +361,17 @@ if (isset($_POST['add_payment_stripe'])) {
         logApp("Stripe", "error", "Exception during PI for invoice ID $invoice_id: $error");
     }
 
-    if ($payment_intent->status == "succeeded" && intval($balance_to_pay) == intval($pi_amount_paid)) {
+    if (isset($payment_intent) && $payment_intent->status == "succeeded" && intval($payment_intent->amount_received) === $balance_cents + $fee_cents) {
 
         // Update Invoice Status
         mysqli_query($mysqli, "UPDATE invoices SET invoice_status = 'Paid' WHERE invoice_id = $invoice_id");
 
+        // The card fee goes on the invoice, so the payment - the invoice and its fee - pays it to the cent
+        billingCardFeeAdd($invoice_id, $fee_cents / 100, $pi_date);
+
         // Add Payment to History
         mysqli_query($mysqli, "INSERT INTO payments SET payment_date = '$pi_date', payment_amount = $pi_amount_paid, payment_currency_code = '$pi_currency', payment_account_id = $account_id, payment_method = 'Stripe', payment_reference = 'Stripe - $pi_id', payment_invoice_id = $invoice_id");
-        mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (agent)', history_invoice_id = $invoice_id");
+        mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (agent)" . ($fee_cents > 0 ? ', with a ' . escapeSql(billingMoney($fee_cents / 100, $pi_currency)) . ' card fee' : '') . "', history_invoice_id = $invoice_id");
 
         // The client's receipt, and the paid notification address - functions/billing_email.php
         if (!empty($config_smtp_provider)) {
@@ -378,10 +389,11 @@ if (isset($_POST['add_payment_stripe'])) {
 
         // Notify/log
         appNotify("Invoice Paid", "Invoice $invoice_prefix$invoice_number automatically paid", "/agent/invoice.php?invoice_id=$invoice_id", $client_id);
-        logAudit("Invoice", "Payment", "$session_name initiated Stripe payment amount of " . numfmt_format_currency($currency_format, $invoice_amount, $invoice_currency_code) . " added to invoice $invoice_prefix$invoice_number - $pi_id $extended_log_desc", $client_id, $invoice_id);
+        $fee_text = $fee_cents > 0 ? ' (with a ' . numfmt_format_currency($currency_format, $fee_cents / 100, $invoice_currency_code) . ' card fee)' : '';
+        logAudit("Invoice", "Payment", "$session_name initiated Stripe payment amount of " . numfmt_format_currency($currency_format, $pi_amount_paid, $invoice_currency_code) . "$fee_text added to invoice $invoice_prefix$invoice_number - $pi_id $extended_log_desc", $client_id, $invoice_id);
         triggerCustomAction('invoice_pay', $invoice_id);
 
-        flashAlert("Payment amount <strong>" . numfmt_format_currency($currency_format, $invoice_amount, $invoice_currency_code) . "</strong> added");
+        flashAlert("Payment amount <strong>" . numfmt_format_currency($currency_format, $pi_amount_paid, $invoice_currency_code) . "</strong>$fee_text added");
 
         redirect();
 
@@ -652,12 +664,24 @@ if (isset($_GET['refund_payment_stripe'])) {
 
     mysqli_query($mysqli,"DELETE FROM payments WHERE payment_id = $payment_id");
 
+    // A card fee the payment carried was refunded with it - its line comes off the invoice too
+    $fee_removed = 0.0;
+    try {
+        $refunded_pi = $stripe->paymentIntents->retrieve($stripe_payment_intent_id);
+        $refunded_fee = intval(billingCardFeeSplit($refunded_pi->metadata->toArray())[$invoice_id] ?? 0) / 100;
+        if ($refunded_fee > 0 && billingCardFeeRemove($invoice_id, $refunded_fee)) {
+            $fee_removed = $refunded_fee;
+        }
+    } catch (Exception $e) {
+        logApp("Stripe", "warning", "Refunded $stripe_payment_intent_id but could not check it for a card fee on invoice ID $invoice_id: " . $e->getMessage());
+    }
+
     // Recalculate from what is left rather than from the pre-delete total
     $invoice_status = updateInvoiceStatusFromPayments($invoice_id);
 
     mysqli_query($mysqli,"INSERT INTO history SET history_status = '$invoice_status', history_description = 'Payment $stripe_payment_intent_id deleted and refunded', history_invoice_id = $invoice_id");
   
-    logAudit("Invoice", "Edit", "$session_name refunded and deleted Payment $stripe_payment_intent_id on Invoice $invoice_prefix$invoice_number", $client_id, $invoice_id);
+    logAudit("Invoice", "Edit", "$session_name refunded and deleted Payment $stripe_payment_intent_id on Invoice $invoice_prefix$invoice_number" . ($fee_removed > 0 ? ', and took off its ' . escapeSql(billingMoney($fee_removed, $invoice_currency_code)) . ' card fee' : ''), $client_id, $invoice_id);
 
     flashAlert("Payment deleted and refunded in Stripe", 'error');
 
diff --git a/agent/recurring_invoice.php b/agent/recurring_invoice.php
index d6e892798..7bc78c8ac 100644
--- a/agent/recurring_invoice.php
+++ b/agent/recurring_invoice.php
@@ -86,6 +86,8 @@ while ($row = mysqli_fetch_assoc($sql)) {
     $saved_methods[intval($row['saved_payment_id'])] = $row;
 }
 $autopay_id = intval($recurring['recurring_payment_saved_payment_id'] ?? 0);
+// The card fee autopay adds, when the client pays one (functions/billing_pay.php)
+$autopay_fee = billingCardFeeFor($client_id);
 
 // Override Tab Title // No Sanitizing needed as this var will only be used in the tab title
 $tab_title = $recurring['client_name'];
@@ -367,7 +369,7 @@ $paper = [
                             </select>
                         </div>
                     </form>
-                    <div class="form-text"><?= $autopay_id ? 'Charged on the due date of each invoice it makes.' : 'Charge a card on file on the due date of each invoice it makes.' ?></div>
+                    <div class="form-text"><?= $autopay_id ? 'Charged on the due date of each invoice it makes.' : 'Charge a card on file on the due date of each invoice it makes.' ?><?= $autopay_fee ? ' With the ' . escapeHtml(billingCardFeeText($autopay_fee, $recurring['recurring_invoice_currency_code'] ?? '')) . ' card fee, as a line on the invoice.' : '' ?></div>
                 <?php } else { ?>
                     <div class="small text-body-secondary">No card on file for <?= escapeHtml($recurring['client_name']) ?>. Once they save one paying an invoice online, it can be charged here automatically.</div>
                 <?php } ?>
diff --git a/client/invoice.php b/client/invoice.php
index d9b268c9d..d1a57e44c 100644
--- a/client/invoice.php
+++ b/client/invoice.php
@@ -40,6 +40,9 @@ $company = billingCompany();
 $owing = in_array($state['state'], ['open', 'overdue'], true) && invoiceCanPay($invoice, $state);
 $cards = billingStripeProvider() !== null;
 $can_pay = $owing && $cards && billingOnlinePayAllowed($state['balance']);
+// The card fee on paying the balance by card, when the client pays one - autopay adds it too
+$fee_rates = $cards ? billingCardFeeFor($session_client_id) : null;
+$card_fee = billingCardFeeCents((int) round($state['balance'] * 100), $fee_rates) / 100;
 
 // The other invoices still owed, to pay with this one
 $others = array_filter(billingClientOpenInvoices($session_client_id), function ($row) use ($invoice_id) {
@@ -122,11 +125,14 @@ $paper = [
                     <?php if ($autopay_card) { ?>
                         <div class="itflow-portal-note mb-3">
                             <i class="<?= escapeHtml($autopay_card['icon']) ?> fa-fw"></i>
-                            <span>Autopay will charge <?= escapeHtml($autopay_card['label']) ?> on <?= escapeHtml(date('M j', strtotime($invoice['invoice_due']))) ?> - nothing to do, unless you would rather pay now.</span>
+                            <span>Autopay will charge <?= escapeHtml($autopay_card['label']) ?><?= $card_fee > 0 ? ' ' . escapeHtml(billingMoney($state['balance'] + $card_fee, $currency)) . ', with a ' . escapeHtml(billingMoney($card_fee, $currency)) . ' card fee,' : '' ?> on <?= escapeHtml(date('M j', strtotime($invoice['invoice_due']))) ?> - nothing to do, unless you would rather pay now.</span>
                         </div>
                     <?php } ?>
                     <?php if ($can_pay) { ?>
                         <a class="btn btn-success btn-lg w-100" href="unpaid_invoices.php?select=<?= $invoice_id ?>"><i class="fas fa-credit-card me-2"></i>Pay <?= escapeHtml(billingMoney($state['balance'], $currency)) ?></a>
+                        <?php if ($card_fee > 0) { ?>
+                            <div class="small text-body-secondary text-center mt-2" title="<?= escapeHtml(billingCardFeeTerms($fee_rates, $currency)) ?>">Plus a <?= escapeHtml(billingMoney($card_fee, $currency)) ?> card fee</div>
+                        <?php } ?>
                         <?php if ($others) { ?>
                             <div class="text-center mt-2"><a class="small" href="unpaid_invoices.php">Or pay it with your <?= count($others) ?> other open <?= count($others) === 1 ? 'invoice' : 'invoices' ?></a></div>
                         <?php } ?>
diff --git a/client/pay.php b/client/pay.php
index aa499bbd4..d70cc58d2 100644
--- a/client/pay.php
+++ b/client/pay.php
@@ -66,7 +66,7 @@ $back = 'unpaid_invoices.php' . ($checkout && !empty($checkout['ids']) ? '?' . h
     </section>
 
 <?php } else {
-    $amount = billingMoney($selection['total'], $selection['currency']);
+    $amount = billingMoney($selection['charge'], $selection['currency']);
     $count = count($selection['invoices']); ?>
 
     <div class="itflow-portal-page-head">
@@ -118,6 +118,15 @@ $back = 'unpaid_invoices.php' . ($checkout && !empty($checkout['ids']) ? '?' . h
                             <span class="itflow-money"><?= escapeHtml(billingMoney($selection['cents'][$id] / 100, $selection['currency'])) ?></span>
                         </li>
                     <?php } ?>
+                    <?php if ($selection['fee'] > 0) { ?>
+                        <li class="itflow-portal-todo" data-pay-fee-line>
+                            <span class="itflow-portal-todo-main">
+                                <div>Card fee</div>
+                                <div><?= escapeHtml(billingCardFeeTerms($selection['fee_rates'], $selection['currency'])) ?></div>
+                            </span>
+                            <span class="itflow-money"><?= escapeHtml(billingMoney($selection['fee'], $selection['currency'])) ?></span>
+                        </li>
+                    <?php } ?>
                 </ul>
                 <div class="itflow-portal-paybar d-flex justify-content-between align-items-baseline">
                     <span class="text-body-secondary">Total</span>
diff --git a/client/post.php b/client/post.php
index 7966a3aec..93e950e5c 100644
--- a/client/post.php
+++ b/client/post.php
@@ -1047,12 +1047,12 @@ if (isset($_POST['portal_pay'])) {
     if (!$booked['ok']) {
         $pi_id = escapeSql((string) $charge['pi']->id);
         logApp("Stripe", "error", "Saved card payment $pi_id for client $session_client_id went through but could not be booked: " . $booked['error']);
-        appNotify("Invoice Payment", "A card payment of " . escapeSql(billingMoney($selection['total'], $selection['currency'])) . " from $session_client_name went through in the client portal but could not be recorded - $pi_id", "/agent/invoices.php?client_id=$session_client_id", $session_client_id);
+        appNotify("Invoice Payment", "A card payment of " . escapeSql(billingMoney($selection['charge'], $selection['currency'])) . " from $session_client_name went through in the client portal but could not be recorded - $pi_id", "/agent/invoices.php?client_id=$session_client_id", $session_client_id);
         flashAlert('Your card was charged, but we could not record the payment here - we have been told and will put it right', 'error');
         redirect('invoices.php');
     }
 
-    flashAlert('Thank you - your payment of <strong>' . escapeHtml(billingMoney($selection['total'], $selection['currency'])) . '</strong> went through');
+    flashAlert('Thank you - your payment of <strong>' . escapeHtml(billingMoney($selection['charge'], $selection['currency'])) . '</strong> went through');
     redirect('receipt.php?id=' . $booked['payment_id']);
 
 }
diff --git a/client/recurring_invoice.php b/client/recurring_invoice.php
index 7eb61d6dd..7b5459c75 100644
--- a/client/recurring_invoice.php
+++ b/client/recurring_invoice.php
@@ -38,6 +38,7 @@ $usable = array_filter($cards, function ($card) {
     return !$card['card']['expired'];
 });
 $autopay = intval($recurring['recurring_payment_saved_payment_id']);
+$fee_rates = $cards_on ? billingCardFeeFor($session_client_id) : null;
 $made = array_filter(recurringInvoiceGenerated($recurring_id, 8), function ($row) {
     return $row['invoice_status'] !== 'Draft';
 });
@@ -92,7 +93,7 @@ $paper = [
                         </div>
                         <div class="form-text">
                             <?php if ($usable) { ?>
-                                Charged on each invoice's due date, with a receipt by email.
+                                Charged on each invoice's due date, with a receipt by email.<?php if ($fee_rates) { ?> Each charge has a card fee added: <?= escapeHtml(billingCardFeeTerms($fee_rates, $currency)) ?>.<?php } ?>
                             <?php } else { ?>
                                 <a href="saved_payment_methods.php">Add a card</a> to have these paid automatically.
                             <?php } ?>
diff --git a/client/saved_payment_methods.php b/client/saved_payment_methods.php
index 0d85edf3e..fcd759d03 100644
--- a/client/saved_payment_methods.php
+++ b/client/saved_payment_methods.php
@@ -48,6 +48,9 @@ $recurring = mysqli_query($mysqli, "SELECT recurring_invoice_id, recurring_invoi
     ORDER BY recurring_invoice_next_date ASC, recurring_invoice_id ASC");
 $company = billingCompany();
 $autostart = isset($_GET['add']) && $customer !== '';
+// The card fee, when the client pays one - said where they agree to charges and turn on autopay
+$fee_rates = billingCardFeeFor($session_client_id);
+$fee_terms = $fee_rates ? ' Each card payment has a card fee added: ' . billingCardFeeTerms($fee_rates) . '.' : '';
 ?>
 
 <div class="itflow-portal-page-head">
@@ -96,7 +99,7 @@ $autostart = isset($_GET['add']) && $customer !== '';
                 <?php if ($customer !== '') { ?>
                     <button type="button" class="btn btn-outline-primary" data-stripe-add-card<?= $autostart ? ' hidden' : '' ?>><i class="fas fa-plus me-2"></i>Add a card</button>
                     <div data-stripe-add-card-holder data-stripe-key="<?= escapeHtml($provider['payment_provider_public_key']) ?>"<?= $autostart ? ' data-autostart' : '' ?> hidden>
-                        <p class="small text-body-secondary">By saving a card you agree <?= escapeHtml($company['company_name'] ?? 'we') ?> may charge it for invoices you pay with it, and for the recurring invoices you set to autopay.</p>
+                        <p class="small text-body-secondary">By saving a card you agree <?= escapeHtml($company['company_name'] ?? 'we') ?> may charge it for invoices you pay with it, and for the recurring invoices you set to autopay.<?= escapeHtml($fee_terms) ?></p>
                         <div class="text-body-secondary small" data-stripe-loading><span class="spinner-border spinner-border-sm me-2" aria-hidden="true"></span>Loading Stripe...</div>
                         <div class="alert alert-warning small mb-0" data-stripe-unavailable hidden>Stripe's form did not load - check your connection and reload the page.</div>
                         <div id="checkout"></div>
@@ -104,7 +107,7 @@ $autostart = isset($_GET['add']) && $customer !== '';
                 <?php } else { ?>
                     <form action="post.php" method="post" data-portal-once>
                         <input type="hidden" name="csrf_token" value="<?= $_SESSION['csrf_token'] ?>">
-                        <p class="small text-body-secondary">By saving a card you agree <?= escapeHtml($company['company_name'] ?? 'we') ?> may charge it for invoices you pay with it, and for the recurring invoices you set to autopay. Stripe keeps the card details, under its privacy policy and terms.</p>
+                        <p class="small text-body-secondary">By saving a card you agree <?= escapeHtml($company['company_name'] ?? 'we') ?> may charge it for invoices you pay with it, and for the recurring invoices you set to autopay.<?= escapeHtml($fee_terms) ?> Stripe keeps the card details, under its privacy policy and terms.</p>
                         <button type="submit" class="btn btn-outline-primary" name="create_stripe_customer"><i class="fas fa-plus me-2"></i>Add a card</button>
                     </form>
                 <?php } ?>
@@ -121,7 +124,7 @@ $autostart = isset($_GET['add']) && $customer !== '';
                 <?= emptyStateHtml(['title' => 'Nothing to autopay', 'text' => 'Recurring invoices - monthly services and the like - can be paid automatically once you have one.', 'icon' => 'fa-sync-alt', 'filtered' => false]) ?>
             <?php } else { ?>
                 <div class="itflow-portal-panel-body">
-                    <p class="small text-body-secondary mb-0">Autopay charges the card on each invoice's due date, and we email you a receipt every time.<?= !$usable ? ' Add a card to turn it on.' : '' ?></p>
+                    <p class="small text-body-secondary mb-0">Autopay charges the card on each invoice's due date, and we email you a receipt every time.<?= escapeHtml($fee_terms) ?><?= !$usable ? ' Add a card to turn it on.' : '' ?></p>
                 </div>
                 <ul class="itflow-portal-list border-top">
                     <?php while ($row = mysqli_fetch_assoc($recurring)) {
diff --git a/client/unpaid_invoices.php b/client/unpaid_invoices.php
index 69f0cef63..ad07d8321 100644
--- a/client/unpaid_invoices.php
+++ b/client/unpaid_invoices.php
@@ -4,7 +4,8 @@
  * Pay invoices - everything still owed, ticked to pay, paid together in one
  * card payment: with a saved card there and then, or a new card on the
  * checkout page (pay.php). ?select=ID,ID ticks just those - the Pay button
- * on an invoice. The total and the button follow the ticks (js/portal.js).
+ * on an invoice. The total and the button follow the ticks (js/portal.js),
+ * with the card fee when the client pays one (billingCardFeeCents()).
  *
  * SCOPING: billingClientOpenInvoices() keys the list to $session_client_id,
  * and post.php (portal_pay) checks the choice again before any charge.
@@ -39,6 +40,9 @@ foreach ($open as $i => $row) {
     }
 }
 $limit_cents = $provider ? (int) round(floatval($provider['payment_provider_threshold']) * 100) : 0;
+// The card fee, worked out again by js/portal.js as the ticks change - in hundredths of a percent and cents
+$fee_rates = $provider ? billingCardFeeFor($session_client_id) : null;
+$fee_cents = billingCardFeeCents($total_cents, $fee_rates);
 $locale = str_replace('_', '-', (string) ($session_company_locale ?: 'en_US'));
 $pay_token = bin2hex(random_bytes(16));
 ?>
@@ -67,7 +71,8 @@ $pay_token = bin2hex(random_bytes(16));
 <?php } else { ?>
 
     <form action="post.php" method="post" data-portal-pay data-portal-once
-        data-pay-currency="<?= escapeHtml($currency) ?>" data-pay-locale="<?= escapeHtml($locale) ?>" data-pay-limit="<?= $limit_cents ?>" data-pay-max="<?= BILLING_PAY_MAX_INVOICES ?>">
+        data-pay-currency="<?= escapeHtml($currency) ?>" data-pay-locale="<?= escapeHtml($locale) ?>" data-pay-limit="<?= $limit_cents ?>" data-pay-max="<?= BILLING_PAY_MAX_INVOICES ?>"<?php if ($fee_rates) { ?>
+        data-pay-fee-percent="<?= (int) round($fee_rates['percent'] * 100) ?>" data-pay-fee-fixed="<?= (int) round($fee_rates['fixed'] * 100) ?>"<?php } ?>>
         <input type="hidden" name="csrf_token" value="<?= $_SESSION['csrf_token'] ?>">
         <input type="hidden" name="pay_token" value="<?= $pay_token ?>">
 
@@ -137,16 +142,34 @@ $pay_token = bin2hex(random_bytes(16));
                         </div>
                     </div>
                     <div class="itflow-portal-paybar">
-                        <div class="d-flex justify-content-between align-items-baseline mb-2">
-                            <span class="text-body-secondary" data-pay-count><?= count($ticked) ?> <?= count($ticked) === 1 ? 'invoice' : 'invoices' ?></span>
-                            <span class="itflow-portal-big-amount itflow-money" data-pay-total><?= escapeHtml(billingMoney($total_cents / 100, $currency)) ?></span>
-                        </div>
+                        <?php if ($fee_rates) { ?>
+                            <div class="d-flex justify-content-between align-items-baseline small">
+                                <span class="text-body-secondary" data-pay-count><?= count($ticked) ?> <?= count($ticked) === 1 ? 'invoice' : 'invoices' ?></span>
+                                <span class="itflow-money" data-pay-subtotal><?= escapeHtml(billingMoney($total_cents / 100, $currency)) ?></span>
+                            </div>
+                            <div class="d-flex justify-content-between align-items-baseline small mb-1">
+                                <span class="text-body-secondary" title="<?= escapeHtml(billingCardFeeTerms($fee_rates, $currency)) ?>">Card fee</span>
+                                <span class="itflow-money" data-pay-fee><?= escapeHtml(billingMoney($fee_cents / 100, $currency)) ?></span>
+                            </div>
+                            <div class="d-flex justify-content-between align-items-baseline mb-2">
+                                <span class="text-body-secondary">Total</span>
+                                <span class="itflow-portal-big-amount itflow-money" data-pay-total><?= escapeHtml(billingMoney(($total_cents + $fee_cents) / 100, $currency)) ?></span>
+                            </div>
+                        <?php } else { ?>
+                            <div class="d-flex justify-content-between align-items-baseline mb-2">
+                                <span class="text-body-secondary" data-pay-count><?= count($ticked) ?> <?= count($ticked) === 1 ? 'invoice' : 'invoices' ?></span>
+                                <span class="itflow-portal-big-amount itflow-money" data-pay-total><?= escapeHtml(billingMoney($total_cents / 100, $currency)) ?></span>
+                            </div>
+                        <?php } ?>
                         <div class="alert alert-warning small py-2" data-pay-limit-note<?= $limit_cents > 0 && $total_cents >= $limit_cents ? '' : ' hidden' ?>>
                             Card payments are limited to under <?= escapeHtml(billingMoney($limit_cents / 100, $currency)) ?> at a time - untick some invoices, or pay another way.
                         </div>
                         <button type="submit" class="btn btn-success btn-lg w-100" name="portal_pay" data-pay-button<?= !$ticked ? ' disabled' : '' ?>>
-                            <i class="fas fa-lock me-2"></i><span data-pay-label><?= $usable ? 'Pay ' : 'Continue to pay ' ?><?= escapeHtml(billingMoney($total_cents / 100, $currency)) ?></span>
+                            <i class="fas fa-lock me-2"></i><span data-pay-label><?= $usable ? 'Pay ' : 'Continue to pay ' ?><?= escapeHtml(billingMoney(($total_cents + $fee_cents) / 100, $currency)) ?></span>
                         </button>
+                        <?php if ($fee_rates) { ?>
+                            <p class="small text-body-secondary text-center mt-2 mb-0">Paying by card adds a card fee: <?= escapeHtml(billingCardFeeTerms($fee_rates, $currency)) ?>. It goes on each invoice as a line.</p>
+                        <?php } ?>
                         <p class="small text-body-secondary text-center mt-2 mb-0">Paid securely through Stripe - your card details never reach us.</p>
                     </div>
                 </section>
diff --git a/cron/nightly_tasks.php b/cron/nightly_tasks.php
index c5607c3f6..07ecc4af4 100644
--- a/cron/nightly_tasks.php
+++ b/cron/nightly_tasks.php
@@ -683,23 +683,31 @@ while ($row = mysqli_fetch_assoc($sql_recurring_payments)) {
                 $stripe = new \Stripe\StripeClient($provider_private_key);
 
                 $balance_to_pay = round($invoice_amount, 2);
-                $pi_description = "ITFlow: $client_name payment of $recurring_payment_currency_code $balance_to_pay for $invoice_prefix$invoice_number";
+                // The card fee, when the client pays it (functions/billing_pay.php) - it goes on the invoice once the charge goes through
+                $balance_cents = (int) round($balance_to_pay * 100);
+                $fee_cents = billingCardFeeCents($balance_cents, billingCardFeeFor($client_id));
+                $pi_metadata = [
+                    'itflow_client_id' => $client_id,
+                    'itflow_client_name' => $client_name,
+                    'itflow_invoice_number' => $invoice_prefix . $invoice_number,
+                    'itflow_invoice_id' => $invoice_id,
+                ];
+                if ($fee_cents > 0) {
+                    $pi_metadata['itflow_fees'] = "$invoice_id:$fee_cents";
+                }
+                $pi_description = "ITFlow: $client_name payment of $recurring_payment_currency_code " . number_format(($balance_cents + $fee_cents) / 100, 2, '.', '')
+                    . ($fee_cents > 0 ? ' (with a ' . number_format($fee_cents / 100, 2, '.', '') . ' card fee)' : '') . " for $invoice_prefix$invoice_number";
 
                 try {
                     $payment_intent = $stripe->paymentIntents->create([
-                        'amount' => intval(round($balance_to_pay * 100)),
+                        'amount' => $balance_cents + $fee_cents,
                         'currency' => $recurring_payment_currency_code,
                         'customer' => $stripe_customer_id,
                         'payment_method' => $stripe_payment_method_id,
                         'off_session' => true,
                         'confirm' => true,
                         'description' => $pi_description,
-                        'metadata' => [
-                            'itflow_client_id' => $client_id,
-                            'itflow_client_name' => $client_name,
-                            'itflow_invoice_number' => $invoice_prefix . $invoice_number,
-                            'itflow_invoice_id' => $invoice_id,
-                        ]
+                        'metadata' => $pi_metadata,
                     ]);
 
                     $pi_id = escapeSql($payment_intent->id);
@@ -717,14 +725,17 @@ while ($row = mysqli_fetch_assoc($sql_recurring_payments)) {
                     continue;
                 }
 
-                if ($payment_intent->status == "succeeded" && intval($balance_to_pay) == intval($pi_amount_paid)) {
+                if ($payment_intent->status == "succeeded" && intval($payment_intent->amount_received) === $balance_cents + $fee_cents) {
 
                     // Update Invoice Status
                     mysqli_query($mysqli, "UPDATE invoices SET invoice_status = 'Paid' WHERE invoice_id = $invoice_id");
 
+                    // The card fee goes on the invoice, so the payment - the invoice and its fee - pays it to the cent
+                    billingCardFeeAdd($invoice_id, $fee_cents / 100, $pi_date);
+
                     // Add Payment to History
                     mysqli_query($mysqli, "INSERT INTO payments SET payment_date = '$pi_date', payment_amount = $pi_amount_paid, payment_currency_code = '$pi_currency', payment_account_id = $account_id, payment_method = 'Stripe', payment_reference = 'Stripe - $pi_id', payment_invoice_id = $invoice_id");
-                    mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (autopay)', history_invoice_id = $invoice_id");
+                    mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (autopay)" . ($fee_cents > 0 ? ', with a ' . escapeSql(billingMoney($fee_cents / 100, $pi_currency)) . ' card fee' : '') . "', history_invoice_id = $invoice_id");
 
                     // The client's receipt, and the paid notification address - functions/billing_email.php
                     if (!empty($config_smtp_provider)) {
@@ -737,7 +748,7 @@ while ($row = mysqli_fetch_assoc($sql_recurring_payments)) {
                     // LOGGING
                     $extended_log_desc = !$pi_livemode ? '(DEV MODE)' : '';
                     appNotify("Invoice Paid", "Invoice $invoice_prefix$invoice_number automatically paid", "/agent/invoice.php?invoice_id=$invoice_id", $client_id);
-                    logAudit("Invoice", "Payment", "Auto Stripe payment amount of " . numfmt_format_currency($currency_format, $invoice_amount, $recurring_payment_currency_code) . " added to invoice $invoice_prefix$invoice_number - $pi_id $extended_log_desc", $client_id, $invoice_id);
+                    logAudit("Invoice", "Payment", "Auto Stripe payment amount of " . numfmt_format_currency($currency_format, $pi_amount_paid, $recurring_payment_currency_code) . ($fee_cents > 0 ? ' (with a ' . numfmt_format_currency($currency_format, $fee_cents / 100, $recurring_payment_currency_code) . ' card fee)' : '') . " added to invoice $invoice_prefix$invoice_number - $pi_id $extended_log_desc", $client_id, $invoice_id);
                     triggerCustomAction('invoice_pay', $invoice_id);
 
                 } else {
diff --git a/db.sql b/db.sql
index 6258fb94b..474ecad4f 100644
--- a/db.sql
+++ b/db.sql
@@ -893,6 +893,7 @@ CREATE TABLE `clients` (
   `client_tax_exempt` tinyint(1) NOT NULL DEFAULT 0,
   `client_tax_exempt_number` varchar(200) DEFAULT NULL,
   `client_tax_exempt_expires` date DEFAULT NULL,
+  `client_card_fee_exempt` tinyint(1) NOT NULL DEFAULT 0,
   `client_abbreviation` varchar(10) DEFAULT NULL,
   `client_notes` text DEFAULT NULL,
   `client_favorite` tinyint(1) NOT NULL DEFAULT 0,
@@ -2164,6 +2165,9 @@ CREATE TABLE `payment_providers` (
   `payment_provider_account` int(11) NOT NULL,
   `payment_provider_expense_vendor` int(11) NOT NULL DEFAULT 0,
   `payment_provider_expense_category` int(11) NOT NULL DEFAULT 0,
+  `payment_provider_card_fee` tinyint(1) NOT NULL DEFAULT 0,
+  `payment_provider_card_fee_percent` decimal(5,2) NOT NULL DEFAULT 0.00,
+  `payment_provider_card_fee_fixed` decimal(15,2) NOT NULL DEFAULT 0.00,
   `payment_provider_created_at` datetime NOT NULL DEFAULT current_timestamp(),
   `payment_provider_updated_at` datetime DEFAULT NULL ON UPDATE current_timestamp(),
   PRIMARY KEY (`payment_provider_id`)
diff --git a/functions/billing_pay.php b/functions/billing_pay.php
index b4a76bb8d..e750b95eb 100644
--- a/functions/billing_pay.php
+++ b/functions/billing_pay.php
@@ -7,7 +7,8 @@
  * cards a client has saved for it.
  *
  * One card payment can pay several invoices. The PaymentIntent carries the
- * split in its metadata - itflow_invoices, "invoice_id:cents,..." - and
+ * split in its metadata - itflow_invoices, "invoice_id:cents,...", and the
+ * card fee each carries in itflow_fees when the client pays one - and
  * billingStripeBook() books it as one payment per invoice, all with the same
  * date and reference ("Stripe - pi_..."). That is how the portal's receipt
  * and payment history, the agent pages and the nightly Stripe fee
@@ -19,15 +20,15 @@ const BILLING_PAY_MAX_INVOICES = 25;
 
 /**
  * Stripe as set up under Admin > Payment Providers, when it is turned on and
- * has its keys - id, keys, threshold and the account payments go to. Null
- * when clients can't pay by card.
+ * has its keys - id, keys, threshold, the account payments go to and the card
+ * fee. Null when clients can't pay by card.
  */
 function billingStripeProvider() {
     global $mysqli;
     static $provider = false;
     if ($provider === false) {
         $provider = mysqli_fetch_assoc(mysqli_query($mysqli, "SELECT payment_provider_id, payment_provider_public_key, payment_provider_private_key,
-                payment_provider_threshold, payment_provider_account
+                payment_provider_threshold, payment_provider_account, payment_provider_card_fee, payment_provider_card_fee_percent, payment_provider_card_fee_fixed
             FROM payment_providers WHERE payment_provider_name = 'Stripe' AND payment_provider_active = 1 LIMIT 1")) ?: null;
         if ($provider && (trim((string) $provider['payment_provider_public_key']) === '' || trim((string) $provider['payment_provider_private_key']) === '')) {
             $provider = null;
@@ -72,6 +73,178 @@ function billingOnlinePayAllowed($amount) {
     return $threshold == 0 || $threshold > round(floatval($amount), 2);
 }
 
+/* ---------------------------------------------------------------- Card fee */
+
+/** The name of the line a card fee goes on the invoice as. */
+const BILLING_CARD_FEE_NAME = 'Card Fee';
+
+/**
+ * The card fee clients pay, when Stripe is set to have them pay it (Admin >
+ * Payment Providers) - ['percent', 'fixed'] as Stripe charges them, or null.
+ * The fee is worked out so Stripe's own fee on everything charged comes out
+ * of it, and what is left is what was owed (billingCardFeeCents()).
+ */
+function billingCardFeeRates($provider = null) {
+    $provider = $provider ?? billingStripeProvider();
+    if (!$provider || !intval($provider['payment_provider_card_fee'] ?? 0)) {
+        return null;
+    }
+    $percent = round(floatval($provider['payment_provider_card_fee_percent'] ?? 0), 2);
+    $fixed = round(floatval($provider['payment_provider_card_fee_fixed'] ?? 0), 2);
+    if ($percent <= 0 && $fixed <= 0) {
+        return null;
+    }
+    return ['percent' => $percent, 'fixed' => $fixed];
+}
+
+/** The card fee a client pays - billingCardFeeRates(), unless they are let off it (No card fee, on the client's Billing tab). */
+function billingCardFeeFor($client_id) {
+    global $mysqli;
+    static $exempt = [];
+    $rates = billingCardFeeRates();
+    $client_id = intval($client_id);
+    if (!$rates || !$client_id) {
+        return $rates;
+    }
+    if (!isset($exempt[$client_id])) {
+        $exempt[$client_id] = intval(mysqli_fetch_row(mysqli_query($mysqli, "SELECT client_card_fee_exempt FROM clients WHERE client_id = $client_id"))[0] ?? 0) === 1;
+    }
+    return $exempt[$client_id] ? null : $rates;
+}
+
+/**
+ * The card fee on paying $cents by card, in cents - 0 without $rates. It is
+ * the percent of everything charged plus the fixed part: (cents + fixed) /
+ * (1 - percent), rounded up to the cent, less cents. Worked in whole numbers
+ * so it comes out the same as the portal's script (js/portal.js).
+ */
+function billingCardFeeCents($cents, $rates) {
+    $cents = intval($cents);
+    if (!$rates || $cents <= 0) {
+        return 0;
+    }
+    $keep = 10000 - (int) round(floatval($rates['percent']) * 100);   // what Stripe leaves, in hundredths of a percent
+    $fixed = (int) round(floatval($rates['fixed']) * 100);
+    if ($keep <= 0) {
+        return 0;
+    }
+    $charge = intdiv(($cents + $fixed) * 10000 + $keep - 1, $keep);
+    return max(0, $charge - $cents);
+}
+
+/**
+ * One card fee shared over the invoices one payment pays, in proportion to
+ * what each comes to - [invoice_id => cents], adding up to $fee_cents.
+ */
+function billingCardFeeShares(array $cents, $fee_cents) {
+    $fee_cents = intval($fee_cents);
+    $pool = array_sum(array_map('intval', $cents));
+    $shares = array_fill_keys(array_keys($cents), 0);
+    if ($fee_cents <= 0 || $pool <= 0) {
+        return $shares;
+    }
+    $remainders = [];
+    $given = 0;
+    foreach ($cents as $id => $amount) {
+        $exact = $fee_cents * intval($amount) / $pool;
+        $shares[$id] = intval(floor($exact));
+        $remainders[$id] = $exact - $shares[$id];
+        $given += $shares[$id];
+    }
+    arsort($remainders);
+    foreach (array_keys($remainders) as $id) {
+        if ($given >= $fee_cents) {
+            break;
+        }
+        $shares[$id]++;
+        $given++;
+    }
+    return $shares;
+}
+
+/** The card fee as it reads - "2.9% + $0.30", "3%" or "$0.50". */
+function billingCardFeeText($rates, $currency = '') {
+    if (!$rates) {
+        return '';
+    }
+    $parts = [];
+    if ($rates['percent'] > 0) {
+        $parts[] = rtrim(rtrim(number_format($rates['percent'], 2, '.', ''), '0'), '.') . '%';
+    }
+    if ($rates['fixed'] > 0) {
+        $parts[] = billingMoney($rates['fixed'], $currency);
+    }
+    return implode(' + ', $parts);
+}
+
+/**
+ * The card fee as it is put to a client - "2.9% of what is charged, plus
+ * $0.30", "3% of what is charged" or "$0.50 a payment". Of what is charged,
+ * fee and all, because that is what the provider takes its percent of.
+ */
+function billingCardFeeTerms($rates, $currency = '') {
+    if (!$rates) {
+        return '';
+    }
+    $percent = $rates['percent'] > 0 ? rtrim(rtrim(number_format($rates['percent'], 2, '.', ''), '0'), '.') . '% of what is charged' : '';
+    $fixed = $rates['fixed'] > 0 ? billingMoney($rates['fixed'], $currency) : '';
+    if ($percent !== '' && $fixed !== '') {
+        return "$percent, plus $fixed";
+    }
+    return $percent !== '' ? $percent : "$fixed a payment";
+}
+
+/**
+ * Put a card fee on an invoice, as a line of its own with no tax, and its
+ * total up by as much - as a payment that carries it is booked. The invoice's
+ * other lines are left as they are, so the payment pays it to the cent. The
+ * line's id, or 0 when there is no fee.
+ */
+function billingCardFeeAdd($invoice_id, $fee, $date = '') {
+    global $mysqli;
+    $invoice_id = intval($invoice_id);
+    $fee = round(floatval($fee), 2);
+    if (!$invoice_id || $fee <= 0) {
+        return 0;
+    }
+    $date = preg_match('/^\d{4}-\d{2}-\d{2}$/', (string) $date) ? $date : date('Y-m-d');
+    $order = intval(mysqli_fetch_row(mysqli_query($mysqli, "SELECT COALESCE(MAX(item_order), 0) + 1 FROM invoice_items WHERE item_invoice_id = $invoice_id"))[0]);
+    mysqli_query($mysqli, "INSERT INTO invoice_items SET item_name = '" . escapeSql(BILLING_CARD_FEE_NAME) . "', item_description = '" . escapeSql("For paying by card on $date") . "',
+        item_quantity = 1, item_price = $fee, item_subtotal = $fee, item_tax = 0, item_total = $fee, item_tax_id = 0, item_product_id = 0, item_order = $order, item_invoice_id = $invoice_id");
+    $item_id = intval(mysqli_insert_id($mysqli));
+    mysqli_query($mysqli, "UPDATE invoices SET invoice_amount = invoice_amount + $fee WHERE invoice_id = $invoice_id");
+    return $item_id;
+}
+
+/**
+ * Take a card fee back off an invoice - the payment that carried it was
+ * refunded. The latest Card Fee line of that amount goes, and the total comes
+ * down by as much. Whether there was one.
+ */
+function billingCardFeeRemove($invoice_id, $fee) {
+    global $mysqli;
+    $invoice_id = intval($invoice_id);
+    $fee = round(floatval($fee), 2);
+    if (!$invoice_id || $fee <= 0) {
+        return false;
+    }
+    $item = mysqli_fetch_row(mysqli_query($mysqli, "SELECT item_id FROM invoice_items
+        WHERE item_invoice_id = $invoice_id AND item_name = '" . escapeSql(BILLING_CARD_FEE_NAME) . "' AND item_total = $fee
+        ORDER BY item_id DESC LIMIT 1"));
+    if (!$item) {
+        return false;
+    }
+    mysqli_query($mysqli, "DELETE FROM invoice_items WHERE item_id = " . intval($item[0]));
+    mysqli_query($mysqli, "UPDATE invoices SET invoice_amount = invoice_amount - $fee WHERE invoice_id = $invoice_id");
+    return true;
+}
+
+/** The card fee each invoice a payment paid carried - [invoice_id => cents] from its metadata (itflow_fees), [] when none. */
+function billingCardFeeSplit($metadata) {
+    $metadata = (array) $metadata;
+    return isset($metadata['itflow_fees']) && (string) $metadata['itflow_fees'] !== '' ? billingPaySplitParse($metadata['itflow_fees']) : [];
+}
+
 /* ------------------------------------------------------------- Saved cards */
 
 /**
@@ -145,8 +318,10 @@ function billingSavedCards($client_id) {
  * The invoices a client chose to pay, checked: theirs, still open with
  * something left on them, in one currency, no more than a card payment can
  * carry. ['invoices' => [id => row, with balance], 'cents' => [id =>
- * cents], 'total', 'currency', 'numbers'] - or null, with $error for the
- * client.
+ * cents], 'total', 'currency', 'numbers', and the card fee when the client
+ * pays it - 'fees' => [id => cents], 'fee', 'charge' (total and fee),
+ * 'fee_rates'] - or null, with $error for the client. The card limit is on
+ * what the invoices come to, without the fee.
  */
 function billingPaySelection($client_id, array $invoice_ids, &$error = '') {
     $invoice_ids = array_values(array_unique(array_filter(array_map('intval', $invoice_ids))));
@@ -187,6 +362,12 @@ function billingPaySelection($client_id, array $invoice_ids, &$error = '') {
             . ' at a time - pay fewer invoices at once, or pay another way';
         return null;
     }
+    // The card fee - one on the whole payment, shared over the invoices it pays
+    $selection['fee_rates'] = billingCardFeeFor($client_id);
+    $fee_cents = billingCardFeeCents(array_sum($selection['cents']), $selection['fee_rates']);
+    $selection['fees'] = $fee_cents ? billingCardFeeShares($selection['cents'], $fee_cents) : [];
+    $selection['fee'] = $fee_cents / 100;
+    $selection['charge'] = (array_sum($selection['cents']) + $fee_cents) / 100;
     return $selection;
 }
 
@@ -212,9 +393,10 @@ function billingPaySplitParse($split) {
 }
 
 /**
- * What every PaymentIntent for a selection carries - amount, currency,
- * description and the metadata billingStripeBook() books from. $by: the
- * contact paying (name).
+ * What every PaymentIntent for a selection carries - amount (with the card
+ * fee), currency, description and the metadata billingStripeBook() books
+ * from: itflow_invoices, what each invoice was owed, and itflow_fees, the card
+ * fee each carries. $by: the contact paying (name).
  */
 function billingStripeIntentParams(array $selection, $client_id, array $by = []) {
     global $mysqli;
@@ -233,10 +415,16 @@ function billingStripeIntentParams(array $selection, $client_id, array $by = [])
         // The one-invoice key the guest and autopay payments carry
         $metadata['itflow_invoice_id'] = intval(array_key_first($selection['cents']));
     }
+    $fee_cents = array_sum($selection['fees'] ?? []);
+    if ($fee_cents > 0) {
+        $metadata['itflow_fees'] = billingPaySplit(['cents' => $selection['fees']]);
+    }
+    $charge = (array_sum($selection['cents']) + $fee_cents) / 100;
     return [
-        'amount' => array_sum($selection['cents']),
+        'amount' => array_sum($selection['cents']) + $fee_cents,
         'currency' => strtolower($selection['currency']),
-        'description' => mb_substr("ITFlow: $client_name payment of {$selection['currency']} " . number_format($selection['total'], 2, '.', '') . " for $numbers", 0, 1000),
+        'description' => mb_substr("ITFlow: $client_name payment of {$selection['currency']} " . number_format($charge, 2, '.', '')
+            . ($fee_cents > 0 ? ' (with a ' . number_format($fee_cents / 100, 2, '.', '') . ' card fee)' : '') . " for $numbers", 0, 1000),
         'metadata' => $metadata,
         'payment_method_types' => ['card'],
     ];
@@ -302,6 +490,7 @@ function billingStripeCheckoutIntent(array $selection, $client_id, array $by = [
             $old = $stripe->paymentIntents->retrieve($reuse_id);
             $waiting = in_array($old->status, ['requires_payment_method', 'requires_confirmation', 'requires_action'], true);
             if ($waiting && intval($old->amount) === intval($params['amount']) && ($old->metadata['itflow_invoices'] ?? '') === $params['metadata']['itflow_invoices']
+                && (string) ($old->metadata['itflow_fees'] ?? '') === (string) ($params['metadata']['itflow_fees'] ?? '')
                 && intval($old->metadata['itflow_client_id'] ?? 0) === intval($client_id)) {
                 return $old;
             }
@@ -320,7 +509,9 @@ function billingStripeCheckoutIntent(array $selection, $client_id, array $by = [
 /**
  * Book a card payment that went through: one payment per invoice in its
  * split, dated the day it was made, into Stripe's account, referenced
- * "Stripe - pi_...", and each invoice's status from its payments. The money
+ * "Stripe - pi_...", and each invoice's status from its payments. A card fee
+ * it carried goes on each invoice as a line first (billingCardFeeAdd()), and
+ * the invoice's payment is what it was owed and its fee. The money
  * has been taken, so an invoice paid some other way meanwhile (now overpaid)
  * or no longer open is booked all the same and flagged to the agents. Booked
  * once: another call for the same payment finds it and books nothing.
@@ -354,11 +545,15 @@ function billingStripeBook($pi, $client_id, array $by = []) {
     if (intval($metadata['itflow_client_id'] ?? 0) !== $client_id) {
         return $fail('not this client');
     }
+    $fees = billingCardFeeSplit($metadata);
+    if (isset($metadata['itflow_fees']) && (string) $metadata['itflow_fees'] !== '' && !$fees) {
+        return $fail('card fee does not read');
+    }
     $split = billingPaySplitParse($metadata['itflow_invoices'] ?? '');
     if (!$split && intval($metadata['itflow_invoice_id'] ?? 0)) {
-        $split = [intval($metadata['itflow_invoice_id']) => $received];
+        $split = [intval($metadata['itflow_invoice_id']) => $received - array_sum($fees)];
     }
-    if (!$split || array_sum($split) !== $received) {
+    if (!$split || array_sum($split) + array_sum($fees) !== $received || array_diff_key($fees, $split)) {
         return $fail('split does not add up');
     }
 
@@ -385,7 +580,7 @@ function billingStripeBook($pi, $client_id, array $by = []) {
         mysqli_query($mysqli, "SELECT RELEASE_LOCK('$lock')");
         $applied = [];
         foreach ($invoices as $invoice_id => $invoice) {
-            $applied[] = ['invoice' => billingRow('invoice', $invoice_id, false), 'amount' => $split[$invoice_id] / 100];
+            $applied[] = ['invoice' => billingRow('invoice', $invoice_id, false), 'amount' => ($split[$invoice_id] + ($fees[$invoice_id] ?? 0)) / 100];
         }
         return ['ok' => true, 'error' => '', 'applied' => $applied, 'payment_id' => intval($booked[0]), 'already' => true];
     }
@@ -402,8 +597,10 @@ function billingStripeBook($pi, $client_id, array $by = []) {
     $first_payment_id = 0;
 
     foreach ($invoices as $invoice_id => $invoice) {
-        $amount = $split[$invoice_id] / 100;
+        $fee = ($fees[$invoice_id] ?? 0) / 100;
+        $amount = ($split[$invoice_id] + ($fees[$invoice_id] ?? 0)) / 100;
         $status_before = (string) $invoice['invoice_status'];
+        billingCardFeeAdd($invoice_id, $fee, $date);
         mysqli_query($mysqli, "INSERT INTO payments SET payment_date = '$date', payment_amount = $amount, payment_currency_code = '" . escapeSql($currency) . "',
             payment_account_id = $account_id, payment_method = 'Stripe', payment_reference = '$reference', payment_invoice_id = $invoice_id");
         $first_payment_id = $first_payment_id ?: intval(mysqli_insert_id($mysqli));
@@ -412,7 +609,7 @@ function billingStripeBook($pi, $client_id, array $by = []) {
         $number = billingNumber('invoice', $invoice);
         $money = billingMoney($amount, $currency);
 
-        billingLog('invoice', $invoice_id, $status, "Paid $money online by card" . ($name !== '' ? " - $name" : '') . ($via !== '' ? " $via" : '')
+        billingLog('invoice', $invoice_id, $status, "Paid $money online by card" . ($fee > 0 ? ', with a ' . billingMoney($fee, $currency) . ' card fee' : '') . ($name !== '' ? " - $name" : '') . ($via !== '' ? " $via" : '')
             . ($many ? ', in one payment of ' . billingMoney($total, $currency) . ' for ' . count($invoices) . ' invoices' : ''));
 
         $state = invoiceState($invoice, invoicePaid($invoice_id));
@@ -424,7 +621,7 @@ function billingStripeBook($pi, $client_id, array $by = []) {
         if ($status === 'Paid') {
             triggerCustomAction('invoice_pay', $invoice_id);
         }
-        logAudit("Invoice", "Payment", escapeSql(($name !== '' ? $name : 'Client') . " paid $money on invoice $number by card" . ($via !== '' ? " $via" : '') . " - $pi_id$dev"), $client_id, $invoice_id);
+        logAudit("Invoice", "Payment", escapeSql(($name !== '' ? $name : 'Client') . " paid $money on invoice $number by card" . ($fee > 0 ? ', with a ' . billingMoney($fee, $currency) . ' card fee' : '') . ($via !== '' ? " $via" : '') . " - $pi_id$dev"), $client_id, $invoice_id);
         $applied[] = ['invoice' => $invoice, 'amount' => $amount];
     }
 
diff --git a/functions/payment_provider.php b/functions/payment_provider.php
index 1f4f652a2..9c477094b 100644
--- a/functions/payment_provider.php
+++ b/functions/payment_provider.php
@@ -5,9 +5,10 @@
  *
  * The services clients pay invoices by card through - Stripe, for now. Each
  * has its keys (live or test, as the keys say), whether it is on, the account
- * its payments go into, the invoices it is too small for (the card limit), and
+ * its payments go into, the invoices it is too small for (the card limit),
  * whether its fees are recorded as expenses - every few minutes, by
- * cron/payment_provider_fees.php. Paying through one is functions/billing_pay.php.
+ * cron/payment_provider_fees.php - and whether clients pay a card fee to cover
+ * them. Paying through one is functions/billing_pay.php.
  *
  * A provider is saved only once it is right: its keys look like that
  * provider's, come from the same mode, and - when they are new or changed -
@@ -77,6 +78,12 @@ function paymentProviderTiesText(array $ties) {
     return $parts[0] ?? '';
 }
 
+/* The card fee clients pay as it reads - "2.9% + $0.30", or "Off". */
+function paymentProviderCardFeeText($row) {
+    $rates = billingCardFeeRates($row);
+    return $rates ? billingCardFeeText($rates) : 'Off';
+}
+
 /* A card limit as it reads - "Under $1,000.00", or "No limit". */
 function paymentProviderLimitText($threshold) {
     $threshold = round(floatval($threshold), 2);
@@ -88,7 +95,8 @@ function paymentProviderLimitText($threshold) {
  * for a new one) - [the columns to save, errors by field]. Keys: one that
  * isn't that provider's shape, or one live and one test, is wrong; a secret
  * left empty stays as saved. Fees are recorded with a vendor and a category,
- * or not at all.
+ * or not at all. The card fee clients pay is a percent and a fixed part, at
+ * least one of them more than nothing; turned off, both stay as saved.
  */
 function paymentProviderCheck(array $post, $before = null) {
     global $mysqli;
@@ -165,6 +173,28 @@ function paymentProviderCheck(array $post, $before = null) {
         }
     }
 
+    // The card fee clients pay - what the provider charges on a card payment. Off, its rates stay as they were for next time.
+    $card_fee = !empty($post['card_fee']) ? 1 : 0;
+    $card_fee_percent = round(floatval($before['payment_provider_card_fee_percent'] ?? 0), 2);
+    $card_fee_fixed = round(floatval($before['payment_provider_card_fee_fixed'] ?? 0), 2);
+    if ($card_fee) {
+        $percent_text = str_replace(['%', ' '], '', trim((string) ($post['card_fee_percent'] ?? '')));
+        $fixed_text = str_replace([',', ' '], '', trim((string) ($post['card_fee_fixed'] ?? '')));
+        if ($percent_text !== '' && (!preg_match('/^\d{1,2}(\.\d{1,2})?$/', $percent_text) || floatval($percent_text) > 15)) {
+            $errors['card_fee_percent'] = 'A percent from 0 to 15, as 2.9.';
+        } else {
+            $card_fee_percent = round(floatval($percent_text), 2);
+        }
+        if ($fixed_text !== '' && (!preg_match('/^\d{1,3}(\.\d{1,2})?$/', $fixed_text) || floatval($fixed_text) > 100)) {
+            $errors['card_fee_fixed'] = 'A sum up to 100, as 0.30.';
+        } else {
+            $card_fee_fixed = round(floatval($fixed_text), 2);
+        }
+        if (!isset($errors['card_fee_percent']) && !isset($errors['card_fee_fixed']) && $card_fee_percent <= 0 && $card_fee_fixed <= 0) {
+            $errors['card_fee_percent'] = "What $name charges on a card payment - a percent, a fixed part or both.";
+        }
+    }
+
     $after = [
         'payment_provider_name' => $name,
         'payment_provider_description' => $description,
@@ -175,6 +205,9 @@ function paymentProviderCheck(array $post, $before = null) {
         'payment_provider_account' => $account_id,
         'payment_provider_expense_vendor' => $vendor_id,
         'payment_provider_expense_category' => $category_id,
+        'payment_provider_card_fee' => $card_fee,
+        'payment_provider_card_fee_percent' => $card_fee_percent,
+        'payment_provider_card_fee_fixed' => $card_fee_fixed,
     ];
     return [$after, $errors];
 }
@@ -260,6 +293,11 @@ function paymentProviderChangeLines(array $before, array $after) {
     if ($fees_before !== $fees_after) {
         $lines[] = "Fees $fees_before → $fees_after";
     }
+    $card_fee_before = paymentProviderCardFeeText($before);
+    $card_fee_after = paymentProviderCardFeeText($after);
+    if ($card_fee_before !== $card_fee_after) {
+        $lines[] = "Card fee clients pay $card_fee_before → $card_fee_after";
+    }
     if (intval($before['payment_provider_active']) !== $after['payment_provider_active']) {
         $lines[] = $after['payment_provider_active'] ? 'Turned on' : 'Turned off';
     }
diff --git a/guest/guest_ajax.php b/guest/guest_ajax.php
index a5c587cc9..4205eb790 100644
--- a/guest/guest_ajax.php
+++ b/guest/guest_ajax.php
@@ -81,21 +81,30 @@ if (isset($_GET['stripe_create_pi'])) {
     $stripe_customer = mysqli_fetch_assoc($stripe_customer_query);
     $stripe_customer_id = $stripe_customer ? escapeSql($stripe_customer['payment_provider_client']) : null;
 
-    $pi_description = "ITFlow: $client_name payment of $invoice_currency_code $balance_to_pay for $invoice_prefix$invoice_number";
+    // The card fee, when the client pays it - as guest_pay_invoice_stripe.php showed it, and booked from itflow_fees on the way back
+    $balance_cents = (int) round($balance_to_pay * 100);
+    $fee_cents = billingCardFeeCents($balance_cents, billingCardFeeFor($client_id));
+    $pi_metadata = [
+        'itflow_client_id' => $client_id,
+        'itflow_client_name' => $client_name,
+        'itflow_invoice_number' => $invoice_prefix . $invoice_number,
+        'itflow_invoice_id' => $invoice_id,
+    ];
+    if ($fee_cents > 0) {
+        $pi_metadata['itflow_fees'] = "$invoice_id:$fee_cents";
+    }
+
+    $pi_description = "ITFlow: $client_name payment of $invoice_currency_code " . number_format(($balance_cents + $fee_cents) / 100, 2, '.', '')
+        . ($fee_cents > 0 ? ' (with a ' . number_format($fee_cents / 100, 2, '.', '') . ' card fee)' : '') . " for $invoice_prefix$invoice_number";
 
     try {
         \Stripe\Stripe::setApiKey($stripe_secret_key);
 
         $paymentIntent = \Stripe\PaymentIntent::create([
-            'amount' => intval(round($balance_to_pay * 100)), // Stripe expects cents
+            'amount' => $balance_cents + $fee_cents, // Stripe expects cents
             'currency' => $invoice_currency_code,
             'description' => $pi_description,
-            'metadata' => [
-                'itflow_client_id' => $client_id,
-                'itflow_client_name' => $client_name,
-                'itflow_invoice_number' => $invoice_prefix . $invoice_number,
-                'itflow_invoice_id' => $invoice_id,
-            ],
+            'metadata' => $pi_metadata,
             'payment_method_types' => ['card'],
             'customer' => $stripe_customer_id,
         ]);
diff --git a/guest/guest_pay_invoice_stripe.php b/guest/guest_pay_invoice_stripe.php
index aa8d14111..d07b960fd 100644
--- a/guest/guest_pay_invoice_stripe.php
+++ b/guest/guest_pay_invoice_stripe.php
@@ -70,6 +70,10 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
     $amount_paid = floatval(mysqli_fetch_assoc($sql_amount_paid)['amount_paid']);
     $balance_to_pay = round($invoice_amount - $amount_paid, 2);
 
+    // The card fee, when the client pays it - guest_ajax.php charges the same
+    $fee_rates = billingCardFeeFor($client_id);
+    $card_fee = billingCardFeeCents((int) round($balance_to_pay * 100), $fee_rates) / 100;
+
     // Get invoice items
     $sql_invoice_items = mysqli_query($mysqli, "SELECT item_name, item_quantity, item_total FROM invoice_items WHERE item_invoice_id = $invoice_id ORDER BY item_id ASC");
 
@@ -125,6 +129,16 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
                                 </td>
                             </tr>
                         <?php } ?>
+                        <?php if ($card_fee > 0) { ?>
+                            <tr class="text-end">
+                                <td colspan="2">Balance</td>
+                                <td><?= numfmt_format_currency($currency_format, $balance_to_pay, $invoice_currency_code) ?></td>
+                            </tr>
+                            <tr class="text-end">
+                                <td colspan="2">Card fee <div class="small text-body-secondary"><?= escapeHtml(billingCardFeeTerms($fee_rates, $invoice_currency_code)) ?></div></td>
+                                <td><?= numfmt_format_currency($currency_format, $card_fee, $invoice_currency_code) ?></td>
+                            </tr>
+                        <?php } ?>
                         </tbody>
                     </table>
                 </div>
@@ -134,9 +148,12 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
         <div class="col-sm offset-sm-1">
             <div class="card">
                 <div class="card-header">
-                    <h3 class="card-title">Payment Total: <strong><?= numfmt_format_currency($currency_format, $balance_to_pay, $invoice_currency_code) ?></strong></h3>
+                    <h3 class="card-title">Payment Total: <strong><?= numfmt_format_currency($currency_format, $balance_to_pay + $card_fee, $invoice_currency_code) ?></strong></h3>
                 </div>
                 <div class="card-body">
+                    <?php if ($card_fee > 0) { ?>
+                        <p class="small text-body-secondary">With a <?= numfmt_format_currency($currency_format, $card_fee, $invoice_currency_code) ?> card fee for paying by card, which goes on the invoice as a line.</p>
+                    <?php } ?>
                     <form id="payment-form">
                         <input type="hidden" id="stripe_publishable_key" value="<?= $stripe_publishable ?>">
                         <input type="hidden" id="invoice_id" value="<?= $invoice_id ?>">
@@ -227,9 +244,17 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
     $amount_paid_previously = floatval(mysqli_fetch_assoc($sql_amount_paid_previously)['amount_paid']);
     $balance_to_pay = $invoice_amount - $amount_paid_previously;
 
+    // The card fee it carried, if the client pays one (guest_ajax.php) - only for this invoice
+    $pi_fees = billingCardFeeSplit($pi_obj->metadata->toArray());
+    $pi_fee_cents = intval($pi_fees[$invoice_id] ?? 0);
+    if (array_diff_key($pi_fees, [$invoice_id => true])) {
+        error_log("Stripe payment error - card fee is not for invoice $invoice_id on $pi_id");
+        exit(WORDING_PAYMENT_FAILED);
+    }
+
     // Compare in whole cents - intval() truncates, which silently accepted an underpayment
     // of up to 99c as payment in full while rejecting a 1c overpayment.
-    if ((int) round($balance_to_pay * 100) !== (int) round($pi_amount_paid * 100)) {
+    if ((int) round($balance_to_pay * 100) + $pi_fee_cents !== (int) round($pi_amount_paid * 100)) {
         error_log("Stripe payment error - Invoice balance does not match amount paid for $pi_id");
         exit(WORDING_PAYMENT_FAILED);
     }
@@ -251,10 +276,13 @@ if (isset($_GET['invoice_id'], $_GET['url_key']) && !isset($_GET['payment_intent
         exit();
     }
 
+    // The card fee goes on the invoice first, so the payment - balance and fee - pays it to the cent
+    billingCardFeeAdd($invoice_id, $pi_fee_cents / 100, $pi_date);
+
     // Add Payment to History
     mysqli_query($mysqli, "INSERT INTO payments SET payment_date = '$pi_date', payment_amount = $pi_amount_paid, payment_currency_code = '$pi_currency', payment_account_id = $stripe_account, payment_method = 'Stripe', payment_reference = 'Stripe - $pi_id', payment_invoice_id = $invoice_id");
     
-    mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (client) - $ip - $os - $browser', history_invoice_id = $invoice_id");
+    mysqli_query($mysqli, "INSERT INTO history SET history_status = 'Paid', history_description = 'Online Payment added (client)" . ($pi_fee_cents > 0 ? ', with a ' . escapeSql(billingMoney($pi_fee_cents / 100, $pi_currency)) . ' card fee' : '') . " - $ip - $os - $browser', history_invoice_id = $invoice_id");
 
     // Notify
     appNotify("Invoice Paid", "Invoice $invoice_prefix$invoice_number has been paid by $client_name - $ip - $os - $browser", "/agent/invoice.php?invoice_id=$invoice_id", $pi_client_id);
diff --git a/guest/guest_view_invoice.php b/guest/guest_view_invoice.php
index 6a26ff1e8..62e9269fd 100644
--- a/guest/guest_view_invoice.php
+++ b/guest/guest_view_invoice.php
@@ -49,6 +49,8 @@ if ($stripe && invoiceCanPay($invoice, $state) && (floatval($stripe['payment_pro
     $stripe_customer = mysqli_fetch_row(mysqli_query($mysqli, "SELECT payment_provider_client FROM client_payment_provider WHERE client_id = $client_id AND payment_provider_id = " . intval($stripe['payment_provider_id']) . " LIMIT 1"));
     $pay_url = ($stripe_customer ? 'guest_pay_invoice_stripe.php' : 'guest_pay_setup_stripe_customer.php') . "?invoice_id=$invoice_id&url_key=$query_key";
 }
+// The card fee on paying by card, when the client pays one (functions/billing_pay.php)
+$card_fee = $pay_url ? billingCardFeeCents((int) round($state['balance'] * 100), billingCardFeeFor($client_id)) / 100 : 0;
 
 $paper = [
     'type' => 'invoice',
@@ -95,7 +97,7 @@ $paper = [
                     <div class="mb-3"><?= invoiceDuePill($state) ?: '<span class="small text-body-secondary">Due ' . escapeHtml($invoice['invoice_due']) . '</span>' ?></div>
                     <?php if ($pay_url) { ?>
                         <a class="btn btn-success btn-lg w-100 mb-2" href="<?= escapeHtml($pay_url) ?>"><i class="fas fa-credit-card me-2"></i>Pay Now</a>
-                        <div class="small text-body-secondary text-center mb-3"><i class="fas fa-lock me-1"></i>Securely, by card</div>
+                        <div class="small text-body-secondary text-center mb-3"><i class="fas fa-lock me-1"></i>Securely, by card<?= $card_fee > 0 ? ' - plus a ' . $money($card_fee) . ' card fee' : '' ?></div>
                     <?php } ?>
                 <?php } ?>
                 <div class="d-flex gap-2 <?= $state['state'] === 'paid' || in_array($state['state'], ['cancelled', 'nonbillable'], true) ? 'mt-3' : '' ?>">
diff --git a/js/portal.js b/js/portal.js
index 246aa4e3f..96c771377 100644
--- a/js/portal.js
+++ b/js/portal.js
@@ -199,15 +199,19 @@
     });
 
     // ---------- Paying invoices ----------
-    // The ticks on Pay invoices: the total, how many, and the button's words
-    // follow them, and a total over the card limit is stopped here as well as
-    // on the server
+    // The ticks on Pay invoices: the total, the card fee, how many, and the
+    // button's words follow them, and a total over the card limit is stopped
+    // here as well as on the server
     document.querySelectorAll('form[data-portal-pay]').forEach(function (form) {
         var boxes = Array.prototype.slice.call(form.querySelectorAll('input[data-pay-cents]'));
         var all = form.querySelector('[data-pay-all]');
         var button = form.querySelector('[data-pay-button]');
         var limit = parseInt(form.getAttribute('data-pay-limit') || '0', 10);
         var max = parseInt(form.getAttribute('data-pay-max') || '0', 10);
+        // The card fee in hundredths of a percent and cents - worked as billingCardFeeCents() does
+        var feeOn = form.hasAttribute('data-pay-fee-percent');
+        var feePercent = parseInt(form.getAttribute('data-pay-fee-percent') || '0', 10);
+        var feeFixed = parseInt(form.getAttribute('data-pay-fee-fixed') || '0', 10);
         var money;
         try {
             money = new Intl.NumberFormat(form.getAttribute('data-pay-locale') || undefined, {style: 'currency', currency: form.getAttribute('data-pay-currency') || 'USD'});
@@ -222,6 +226,14 @@
             }
         }
 
+        function cardFee(cents) {
+            var keep = 10000 - feePercent;
+            if (!feeOn || cents <= 0 || keep <= 0) {
+                return 0;
+            }
+            return Math.max(0, Math.floor(((cents + feeFixed) * 10000 + keep - 1) / keep) - cents);
+        }
+
         function update() {
             var cents = 0;
             var count = 0;
@@ -235,10 +247,13 @@
                     row.classList.toggle('is-selected', box.checked);
                 }
             });
-            var amount = money.format(cents / 100);
+            var fee = cardFee(cents);
+            var amount = money.format((cents + fee) / 100);
             var method = form.querySelector('input[name=method]:checked');
             var over = limit > 0 && cents >= limit;
             var tooMany = max > 0 && count > max;
+            text('[data-pay-subtotal]', money.format(cents / 100));
+            text('[data-pay-fee]', money.format(fee / 100));
             text('[data-pay-total]', amount);
             text('[data-pay-count]', count + (count === 1 ? ' invoice' : ' invoices'));
             text('[data-pay-label]', !count ? 'Tick an invoice to pay' : (tooMany ? 'Pay up to ' + max + ' invoices at a time'