Interchange-Plus vs Tiered vs Flat Rate: Which Costs Less?

Two providers can quote you “2.9%” and cost you wildly different amounts. The number matters far less than the pricing model behind it — and there are only three you need to understand.

Flat rate

One published percentage on every transaction, regardless of card type. Simple, predictable, and what most aggregator apps use. You pay the same for a debit card that costs the processor very little and a rewards card that costs a lot — which means you subsidize the expensive transactions and overpay on the cheap ones. Fine at low volume. Expensive once you scale, and it hides whether downgrades are happening at all.

Tiered

Transactions are sorted into buckets — typically qualified, mid-qualified and non-qualified — each with its own rate. The catch: your processor decides which transactions land in which bucket, and the rules aren’t published. The advertised rate is always the qualified one, and in practice a large share of real-world transactions arrive somewhere more expensive. Of the three models, this is the one where the gap between the quote and the bill is widest.

Interchange-plus

You pay the actual interchange and assessments, plus a disclosed, fixed markup. Your statement shows all three components separately. It usually looks more complicated and more expensive at a glance — because you’re finally seeing costs the other models bundled out of sight. For most established merchants it is the cheapest of the three and, more importantly, the only one you can audit.

Which one fits you

• Under roughly $10,000 a month: flat rate’s simplicity is often worth the premium.
• Growing past that, or B2B at any size: interchange-plus almost always wins — and it’s the only model where Level 2 and Level 3 savings actually reach you.
• Tiered: hard to recommend. If you’re on it, request a re-quote on interchange-plus and compare effective rates over three months.

The comparison that can’t be gamed

Ignore quoted rates entirely. Ask each provider what your effective rate would have been on last month’s actual volume, and make them show the arithmetic against your real statement. Anyone unwilling to do that is quoting you a number they don’t expect you to end up paying. Our walkthrough on merchant account fees covers the line items that belong in that calculation.

High-risk changes the math, not the logic

If your industry carries elevated risk, your margin will be higher than a low-risk retailer’s — that’s the price of an account that stays open. What shouldn’t change is transparency: you should still be able to see interchange, assessments and markup as separate numbers.

Priced so you can check the work

At Creditcard Payment Services, we place merchant accounts on pricing you can verify against your own statement — for retail and for the industries other banks avoid. Since 2009, most approvals in 2–3 business days.

Not sure which model you’re on? Apply online or call 1-800-475-6011 and we’ll tell you from one statement. No cost, no obligation.