How to use the credit card surcharge calculator
- 1Enter the sale amount before any surcharge.
- 2Enter your processing rate and fixed fee per transaction. Use your effective rate from a recent statement if you can.
- 3Choose the card type. Debit and prepaid cards cannot be surcharged in the US, even when run as credit.
- 4Check the surcharge cap. It starts at Visa’s 3%; lower it to your own cost of acceptance if that is less.
- 5Read the surcharge that covers your fee, the surcharge you are allowed to add, the total the customer pays and what you keep.
Why a surcharge equal to your rate does not cover the fee
Your processor charges its fee on the whole amount the customer pays, and that includes the surcharge. If your rate is 2.9% and you add 2.9% to a $100 sale, the processor takes 2.9% of $102.90, so you are still about $0.08 short, and the fixed fee is not covered at all.
To cover the fee exactly, gross the price up: add the fixed fee to the sale, then divide by one minus the rate. The surcharge is the difference between that total and the sale.
Total to charge = (Sale + Fixed fee) ÷ (1 − Rate) Surcharge = Total to charge − Sale Surcharge % = Surcharge ÷ Sale × 100
Visa and Mastercard surcharge caps in the US
Visa lets US merchants surcharge credit cards only, and caps the surcharge at the lower of your merchant discount rate for that card or 3% of the transaction. Mastercard caps it at the lower of your average effective merchant discount rate for Mastercard credit cards or 4%. In practice, if you surcharge every card brand at one rate, 3% is the ceiling.
Both networks require you to tell your acquirer (your processor) at least 30 days before you start, to show the surcharge clearly at the store entrance or first page of checkout and at the point of sale, and to print it as a separate line on every receipt.
Because a fixed fee pushes the full cost of a small sale above 3%, the surcharge you are allowed to add will not always cover your fee. The calculator shows both numbers.
Visa’s rules are from its U.S. Merchant Surcharge Q&A and Mastercard’s from its merchant surcharge rules page, checked November 2026. A Visa and Mastercard merchant settlement received preliminary court approval in 2026 and could change these rules once final, so check with your processor.
Allowed surcharge = Sale × the lower of (Cap %, your merchant discount rate)
Debit cards, prepaid cards and state laws
You cannot surcharge debit cards or prepaid cards in the US, including a debit card that the customer runs as credit. The Durbin rules on debit fees and the network rules both forbid it. You can offer a discount for cash or debit instead, which follows different rules.
Some states go further. Visa lists Connecticut, Maine, Massachusetts and Puerto Rico as banning credit card surcharges, and Colorado, Minnesota, New Jersey and New York as having their own requirements. Colorado caps surcharges at 2%. New York requires the credit card price to be shown, and the surcharge cannot exceed what the card costs you. Oklahoma lifted its ban from November 1, 2025, with a cap of 2% or your actual processing cost, whichever is less.
California’s pricing rules and other local consumer laws can also affect how a surcharge must be shown. State laws change often and this is not legal advice; check your state attorney general’s guidance or ask an adviser before you surcharge.
Outside the US: UK and EU
The UK has banned surcharges on consumer debit and credit cards since January 13, 2018. The EU bans surcharges on consumer cards covered by the interchange fee caps, which includes most consumer Visa and Mastercard cards. In both, you can still build card costs into your prices or offer a discount for another payment method.
Australia and Canada allow surcharging with limits, so check your own country’s rules. The gross-up maths in this calculator works anywhere; only the legal limits differ.
Worked example
A US repair shop bills $100 and pays its processor 2.9% + $0.30 on credit cards. It wants to pass the fee on and surcharges all card brands at one rate, so it uses Visa’s 3% cap.
| Sale before surcharge | $100.00 |
| Total that covers the fee ($100.30 ÷ 0.971) | $103.30 |
| Surcharge that covers the fee | $3.30 (3.30% of the sale) |
| Highest surcharge allowed (3% cap) | $3.00 |
| Customer pays | $103.00 |
| Processing fee on $103.00 (2.9% + $0.30) | $3.29 |
| Shop keeps | $99.71 |
The full fee would need a 3.30% surcharge, above Visa’s cap, so the shop adds $3.00 and absorbs $0.29. At 2.9% + $0.30 the fee-covering surcharge stays above 3% on any sale under about $2,300. On a lower rate of 2.5% + $0.10, a $500 sale needs only $12.92 (2.58%), so the whole fee fits under the cap.