Free tool
Flat-rate vs interchange-plus calculator
Enter your monthly volume and rough debit share, then the two quotes you are comparing. We estimate the monthly cost of each and the annual difference.
- Flat rate — monthly
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- Interchange-plus — monthly
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- Cheaper option / yr savings
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Estimate only. Interchange is modelled at ~0.05% + 22¢ for the debit portion and ~1.80% + 10¢ for the rest. Get real quotes on a month of your own transactions before switching.
Flat-rate vs interchange-plus, in plain terms
Flat-rate charges the same headline rate on every card, blending the processor's markup into one number. It is predictable and cheap to start, but you overpay on debit and low-reward cards. Interchange-plus passes the wholesale cost through and adds a fixed, disclosed markup — cheaper for most established businesses and far easier to audit, at the cost of a busier statement and usually a monthly fee.
Frequently asked questions
Which pricing model is cheaper?
For low volume, flat rate. As volume grows — and especially if a large share of your sales are debit — interchange-plus usually wins because you pay the real (low) cost on debit instead of a blended average.
What is a typical interchange-plus markup?
A competitive small-business markup is roughly 0.15%–0.35% plus 8¢–15¢ per transaction, on top of pass-through interchange and assessments (~1.7%–1.9% for a card-present retail mix).
Why does debit percentage matter so much?
US regulated debit interchange is capped near 0.05% + 22¢ — far below credit. A flat 2.6% overcharges those transactions by roughly 5×, and interchange-plus passes the low cost straight through.
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Want a processor that actually beats these numbers?
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