Interchange-plus vs. flat-rate pricing
Interchange-plus often fits merchants with consistent volume who want an itemized view of what they pay; flat-rate often fits very low-volume or seasonal businesses that value one predictable number over line-item detail.
General information, not a quote or legal advice. Actual pricing depends on underwriting and your merchant agreement. Last reviewed: September 11, 2026.
Interchange-plus
You pay the interchange and card-brand assessments that apply to each transaction, plus a processor markup, and the statement itemizes each piece. Interchange generally flows to the issuing bank; card-brand assessments are separate network fees; processor and other fees vary by agreement and are disclosed in writing.
Flat-rate
You pay one blended percentage (sometimes plus a per-transaction fee) regardless of card type. The processor absorbs the difference between what low-cost debit cards actually cost and what expensive rewards cards actually cost, and prices everything at one average.
Interchange-plus vs. flat-rate at a glance
| Feature | Interchange-plus | Flat-rate |
|---|---|---|
| Cost structure | Interchange + disclosed markup | One blended rate |
| Statement transparency | Itemized | Blended, not itemized |
| Predictable monthly total | Varies with card mix | Easier to predict |
| Best fit by volume | Growing / established volume | Very low or seasonal volume |
| Rewards-card handling | Priced at real interchange | Absorbed into the blend |
| Quote requires statement review | Yes | No |
| Typical cost at scale | Often lower at higher volume, depending on card mix | Stays flat regardless of volume |
Interchange-plus
- Itemized view of interchange and assessments vs. what the processor charges
- Can lower total cost at meaningful transaction volume, depending on card mix and your agreement
- Markup is disclosed in writing, separate from interchange — not a moving blend
- Rewards and corporate cards are priced at their real (higher) interchange, not hidden in an average
- Statements have more line items and take longer to read
- Monthly cost varies with card mix, so it is harder to predict to the cent
- Needs a statement review to quote accurately — no instant number over the phone
Flat-rate
- One number, easy to explain and budget around
- No statement literacy required — nothing to itemize or reconcile
- Fast to set up; common for very small or seasonal merchants
- The blend is set to cover a range of card types, so merchants with mostly lower-cost cards may pay more than their actual card mix would cost
- No itemized view of how much goes to interchange and assessments vs. the processor
- Can cost more than interchange-plus once volume grows, depending on card mix
When to choose each model
Interchange-plus
Choose interchange-plus once you have consistent monthly volume and want your rate to reflect your actual card mix rather than someone else’s average. It also makes sense the moment you want to audit your processor — with an itemized statement you can verify the markup is what was promised, in writing, every month.
Flat-rate
Choose flat-rate if your volume is small enough that the difference in total dollars barely matters, or if simplicity is worth more to you than optimizing every basis point — for example a pop-up, a seasonal stand, or a side business you run a few hours a week.
Frequent questions
Can I switch from flat-rate to interchange-plus later?
Often, yes — it is a common move once volume grows enough that the itemized model may fit better. The switch is subject to re-underwriting rather than a rebuild of your setup; hardware and integrations typically carry over.
Which model is cheaper for my specific business?
It depends on your case — card mix, average ticket, and monthly volume all move the answer. Request a statement review and get a written comparison instead of a guess.
Does interchange-plus mean unpredictable bills?
The processor markup is disclosed in writing, and any change follows the notice terms in your merchant agreement. The total varies mainly because interchange varies by card type — the same sale on a debit card and on a rewards card carries different interchange. Interchange generally flows to the issuing bank; card-brand assessments are separate network fees; processor and other fees vary by agreement and are disclosed in writing.
Request a statement review. We’ll show you both models, in writing.
No commitment. We’ll tell you which pricing model actually fits your volume and card mix — not which one sounds better on a call.