About the Credit Card Surcharge Calculator
This credit card surcharge calculator shows how much to add to a sale so the customer, not your business, covers the card processing fee. Enter the sale amount, your processor’s percentage and fixed fee, and choose a method: a simple surcharge (price × fee rate) or a gross-up that solves for the total you must charge so that, after fees, you keep exactly the original price.
It is useful for retailers, contractors, medical and professional offices, and anyone invoicing by card who wants to price a convenience fee or surcharge correctly. It also shows what you actually net after the fee is taken from the larger total — the reason a simple 3% surcharge on a 3% fee still leaves you slightly short.
Surcharging is regulated. In the US, card network rules generally limit a surcharge to your actual cost of acceptance and set a maximum percentage, require disclosure at the point of sale and on receipts, and do not allow surcharges on debit or prepaid cards; a few states restrict or prohibit the practice. Use the cap field to stay within the limit that applies to you, and check your processor’s rules and local law before you start.
With the default inputs, the surcharge to add is $3.00. Change any value above to recalculate instantly.
How to use the credit card surcharge calculator
- 1Enter the sale amount before any surcharge.
- 2Enter your processor’s percentage and per-transaction fee.
- 3Choose a simple surcharge or a full gross-up.
- 4Set the maximum surcharge allowed for your business (or 0 for none).
- 5Read the surcharge, the customer’s total and what you net after fees.
Formula and method
A simple surcharge multiplies the sale amount P by the processing rate r and adds any fixed fee f. Because the processor charges its percentage on the whole transaction — including the surcharge — the merchant still loses a small amount: on a $100 sale with a 3% fee, a $3 surcharge creates a $103 charge with a $3.09 fee.
The gross-up method solves for the total T where T × (1 − r) − f = P, so T = (P + f) ÷ (1 − r) and the surcharge is T − P. This recovers the fee exactly, but the surcharge percentage ends up higher than the fee rate. If a cap is set, the surcharge is limited to cap × P, and the shortfall shows what you still absorb.
- P
- Sale amount before surcharge
- r
- Processing fee rate (decimal)
- f
- Fixed fee per transaction
- S
- Surcharge added to the sale
Worked examples
$100 sale, 3% fee, simple surcharge
A 3% surcharge adds $3, so the customer pays $103. The processor charges 3% of $103 = $3.09, leaving you $99.91 — nine cents short of a full pass-through.
Gross-up a 2.9% + $0.30 fee with no cap
The total must satisfy T × 0.971 − 0.30 = 100, so T = $100.30 ÷ 0.971 = $103.30. The $3.30 surcharge (3.30% of the sale) means you keep exactly $100 after fees.
Same gross-up limited by a 3% cap
The 3.30% gross-up exceeds the 3% cap, so the surcharge is held at $3. The fee on $103 is $2.99 + $0.30 = $3.29, and you net $99.71, absorbing about 29 cents.
Frequently asked questions
How do I calculate a credit card surcharge?+
Multiply the sale amount by your processing rate and add any fixed fee — for example $200 × 3% = $6. To recover the fee exactly, divide (sale + fixed fee) by (1 − rate) and subtract the sale amount.
Is it legal to add a credit card surcharge?+
In most US states it is, provided you follow card network rules: register or notify your processor, disclose the surcharge at entry and checkout, show it on the receipt and keep it within the allowed maximum. A few states restrict or prohibit it, so check local law.
Can I surcharge debit cards?+
No. In the US, surcharges are not allowed on debit or prepaid card transactions, even when a debit card is run as credit. Many merchants offer a cash discount program instead, which follows separate rules.
What is the difference between a surcharge and a convenience fee?+
A surcharge is a percentage added for paying by credit card. A convenience fee is typically a flat charge for using an alternative payment channel, such as paying online or by phone, and must apply regardless of card type.
Why does a 3% surcharge not fully cover a 3% fee?+
Because the processor charges its percentage on the surcharge too. A 3% fee on a $103 total is $3.09, so you are short by 3% of the $3 surcharge. The gross-up method closes this gap.
Results are general estimates and not legal advice. Laws vary by jurisdiction — consult a qualified attorney.