Flat rate vs interchange-plus calculator
Price one month of your card sales both ways: one flat rate on every card, or your actual interchange and network costs plus a markup. You'll see which comes out lower on your numbers, and by how much.
Compare the two pricing models
These are made-up example values, filled in so you can see how it works. Replace each one with your own numbers.
Results for the example values
- Flat rate, per month
- $725.00
- Effective rate 2.90%
- Interchange-plus, per month
- $600.00
- Effective rate 2.40%: $462.50 interchange and network, $137.50 markup
- Difference per month
- $125.00
- Difference per year
- $1,500.00
Interchange-plus costs $125.00 less a month on these numbers, or $1,500.00 less a year.
Average ticket: $50.00 across 500 transactions. Monthly fees aren't included, so add any that a quote carries to that side.
How the calculator prices each model
For the flat rate, it takes your volume times the flat percentage and adds the flat fee once for every transaction. For interchange-plus, it adds your interchange and network percentage to the markup percentage, applies the sum to your volume, then adds both per-transaction amounts for every sale.
Each effective rate is that model's monthly cost divided by your volume, times 100. The difference is the flat-rate cost minus the interchange-plus cost, and a year is 12 months at the same pace.
The example, worked through
The prefilled numbers are made up: $25,000.00 of card sales across 500 transactions, a flat rate of 2.70% plus $0.10, an interchange-plus markup of 0.35% plus $0.10, and interchange and network costs that average 1.65% plus $0.10.
- Flat rate: 2.70% of $25,000.00 is $675.00. Add 500 fees of $0.10, or $50.00, and the month costs $725.00, an effective rate of 2.90%.
- Interchange-plus: 1.65% plus 0.35% is 2.00%, and 2.00% of $25,000.00 is $500.00. The two per-transaction amounts add $0.20 on each of 500 sales, or $100.00, for $600.00 in all, an effective rate of 2.40%.
- Difference: $125.00 a month, or $1,500.00 a year, lower on interchange-plus.
Now change the transactions to 2,500, an average ticket of $10.00, and the answer flips. The flat rate comes to $925.00 and interchange-plus to $1,000.00, because the interchange-plus side charges two per-transaction amounts on every sale.
Where to find your interchange and network costs
On an interchange-plus statement, each interchange category gets its own line, and card network fees sit in a section of their own. Add both together, divide by your monthly volume and multiply by 100. Enter that as the percentage, with $0.00 per transaction, since the per-item charges are already inside the total.
Flat-rate and tiered statements leave interchange out, so you can't read it off the page. Ask the interchange-plus provider to price your last month, or send us the statement for a free statement review and we'll do it. Our explainers on what interchange fees are and how to read a merchant statement show what each line means.
Why the cheaper model can change
Small tickets put more weight on per-transaction fees, which is why the example flips at $10 a sale. Card mix matters too: debit costs far less in interchange than rewards credit, so a debit-heavy business gets more out of interchange-plus. And a monthly fee on either quote counts against it, which can decide the result at low volume.
This calculator leaves monthly, statement, PCI and gateway fees out. If a quote carries one, add it to that side before you decide. Our interchange-plus vs flat rate guide works through four made-up businesses, from an $8 coffee ticket to a $400 contractor invoice.
We price on interchange-plus, but the right model is the one that costs you less. If a flat rate wins on your numbers, that's your answer.
Sources
Checked October 12, 2026. Visa's and Mastercard's pages and their current U.S. interchange schedules show interchange changing with the card product and with in-person or card-not-present sales. Regulation II caps debit interchange at large issuers, and the Richmond Fed says a merchant's cost of taking a credit card typically runs 1.5% to 3.5% of each sale, with credit interchange unregulated. The prefilled values are made-up examples, not anyone's actual rates.
- Credit Card Processing Fees & Interchange Rates (Visa) (usa.visa.com)
- Visa USA Interchange Reimbursement Fees (rates effective April 18, 2026) (usa.visa.com)
- Mastercard Interchange Fees and Rates Explained (mastercard.com)
- Mastercard 2026-2027 U.S. Region Interchange Programs and Rates (mastercard.com)
- Regulation II: Debit Card Interchange Fees and Routing, compliance guide (Federal Reserve) (federalreserve.gov)
- Should Credit Card Fees Be Regulated? (Federal Reserve Bank of Richmond, Econ Focus, Fourth Quarter 2025) (richmondfed.org)
Pricing comparison questions
Where do I get my average interchange and network cost?
From an interchange-plus statement: add the interchange lines and the card network fee lines, divide by your volume, and multiply by 100. Flat-rate and tiered statements leave interchange out, so ask a provider to price your last month on interchange-plus, or send it to us for a free statement review.
When does a flat rate come out cheaper?
Usually when tickets are small and the interchange-plus quote charges a per-transaction markup, when volume is low and the interchange-plus side carries monthly fees, or when most of your sales carry high interchange, such as rewards and business cards or keyed-in sales. Run your own numbers both ways instead of assuming.
Does this comparison include monthly or annual fees?
No. It prices only the percentage and per-transaction parts of each quote. If either quote adds a monthly, annual, statement, PCI or gateway fee, add it to that side yourself. At low volume, one monthly fee can be enough to change which model costs less.
Why do the results change when only the transaction count changes?
Per-transaction fees are charged on every sale, whatever its size. More transactions on the same volume means a smaller average ticket and more fixed fees, and the interchange-plus side here carries two per-transaction charges: one for interchange and network fees, one for the markup. That's why a coffee counter and a contractor can get opposite answers from the same two quotes.
Disclaimer: general information, not professional advice
This page is general educational information, not legal, tax, accounting or financial advice. Rules and rates vary by place and change, so confirm them with the official source and a qualified professional before you act. Full terms are in our Terms of Service.
Free for every merchant
Get a Free Statement Review
Send us your most recent processing statement and we'll show you every fee on it, line by line. No commitment, no pressure.