Interchange-plus vs. flat-rate pricing
Interchange-plus is better for merchants with real volume who want to see exactly what they pay; flat-rate is better for very low-volume or seasonal businesses that value one predictable number over line-item detail.
Interchange-plus
You pay the actual interchange and assessment set by Visa/Mastercard/etc. for each transaction, plus a fixed markup the processor discloses in writing. The statement itemizes both pieces, so the only negotiable number is the markup — everything else is set by the card networks and identical across processors.
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 | Opaque |
| Predictable monthly total | Varies with card mix | Yes |
| 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 | Lower as volume grows | Stays flat regardless of volume |
Interchange-plus
- Full visibility into what the network charges vs. what the processor charges
- Usually the lowest total cost at meaningful transaction volume
- Markup is a fixed, written number — 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 has to cover the processor’s worst-case card mix, so low-cost-card merchants overpay
- No visibility into how much goes to the card networks vs. the processor
- Usually more expensive than interchange-plus once volume grows
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?
Yes — it is a common move once volume grows enough that the itemized model starts winning. The switch itself is a re-underwriting, not 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. Send three statements and get a written comparison in 48 hours instead of a guess.
Does interchange-plus mean unpredictable bills?
The markup is fixed and disclosed, so it never changes without notice. The total varies only because interchange itself varies by card type — the same transaction on a debit card and a rewards card genuinely cost the network different amounts.
Send three statements. 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.