How card processing fees are calculated
Online payment processing is almost always priced as a percentage of the transaction plus a fixed fee per transaction, sometimes with a monthly account or gateway fee on top. This calculator multiplies the transaction amount by your rate, adds the fixed fee, and shows what actually lands in your bank account. Monthly totals are built from the rounded per-transaction fee shown above them, so the numbers on screen reconcile if you check them by hand.
This page does not decide your rate. Published rates differ by processor, pricing plan, card type, industry and negotiated volume, and interchange-plus pricing changes with every card brand and card tier. Enter the rate from your own processor agreement or statement. If you run card-present and card-not-present sales, or accept ACH alongside cards, run each one separately - the rates are rarely the same.
Written as of September 2026. Chargebacks, refunds (where the fixed fee is often not returned), currency conversion and instant-payout charges are not included here. Check your monthly processing statement for the definitive numbers and talk to your accountant about how to record them.
Frequently asked questions
Your monthly processing statement lists it. You can also work backwards: divide one month of total fees by that month of total card volume to get the effective rate you are actually paying, then enter that figure.
A flat per-transaction fee is a much larger share of a small sale than a large one. Run a typical small ticket and a typical large ticket through the calculator and compare the effective rate line to see the gap.