Interchange Plus vs Flat Rate vs Tiered: Which Pricing Model Costs You More?

Three models: very different outcomes

Almost every merchant is on one of three processing pricing structures, and most don’t know which one they’re on, let alone whether it’s the right fit for their business. Here’s a plain-English breakdown of each, who it’s actually designed for, and where merchants most commonly get hurt.

Flat rate

Flat rate pricing charges a single percentage on every transaction, regardless of card type. Stripe and Square are the most common examples: 2.6% + $0.10 for in-person swipe or tap.

Who it works for: Low-volume businesses, new merchants, and those who value simplicity above all else. For a business doing under $5K/month, the predictability has genuine value.

Where you get hurt: Flat rate doesn’t adjust for your actual interchange costs, which vary significantly by card type. When you process a basic debit card, the actual interchange cost is often under 0.5%, but you’re still paying 2.6%. The processor keeps the entire spread. At higher volumes, this gap becomes substantial.

Tiered pricing

Tiered pricing buckets transactions into “qualified,” “mid-qualified,” and “non-qualified” categories, each with a different rate. The qualified rate is the one advertised. Everything else costs more, sometimes significantly more.

Who it works for: Frankly, tiered pricing primarily benefits processors, not merchants. The tier classifications are defined and controlled by the processor.

Where you get hurt: Rewards cards, corporate cards, and any card that isn’t a standard consumer card frequently gets pushed to higher tiers. In many businesses, 40–60% of transactions never qualify for the advertised rate. You won’t know this until you read your statement carefully, and most merchants don’t.

Interchange-plus

Interchange-plus pricing passes the actual interchange cost (set by Visa/Mastercard, non-negotiable for anyone) directly to you, then adds a fixed markup on top. For example: “Interchange + 0.3% + $0.10.” This is fully transparent, you can see exactly what Visa charged, and exactly what the processor added.

Who it works for: Any merchant doing consistent volume, generally $10K/month and above. The transparency means you know exactly what you’re paying and why, and the markup portion is negotiable.

Where you can still overpay: The markup percentage varies widely between processors. A markup above 0.5% is high. A well-structured interchange-plus arrangement typically sits at 0.15–0.3% with a low per-transaction fee.

How to find out which model you’re on

Check your processing statement. One or two uniform rates applied across all transactions = flat rate. Categories labeled “qualified,” “mid-qualified,” or “non-qualified” = tiered. “Interchange” shown as its own line item with a separate markup = interchange-plus.

PAIR’s free audit identifies your pricing model, explains what you’re actually paying versus what’s fair, and recommends the right structure for your volume and card mix. We’re not a comparison engine that spits out options, we’ve identified a proven processing structure that works, and we’ll tell you plainly whether it makes sense for your business. If you’re already on a strong arrangement, we’ll tell you that too.

How to Find Out Which Pricing Model You Are On

Look at your most recent processing statement.

If every transaction shows the same rate regardless of card type, you’re on flat rate. If you see “qualified,” “mid-qualified,” and “non-qualified” categories, you’re on tiered. If you see “interchange” as a line item followed by a separate markup, you’re on interchange-plus.

Most merchants on tiered pricing don’t realize it until they look. The advertised rate only applies to a fraction of their transactions.

Why Interchange-Plus Is Almost Always the Right Choice at Volume

Interchange-plus pricing passes the actual network cost directly to you, then adds a fixed, transparent markup on top.

You can see exactly what Visa charged, and exactly what your processor added. That transparency is the point: there’s nowhere to hide inflated margins.

At $10,000/month or above, the math consistently favors interchange-plus over flat rate. At $30,000/month, the savings are often $200–$400/month compared to a standard flat-rate plan.

The downside is that your monthly cost varies slightly based on card mix. But for most merchants, that variability is worth the savings.

The Dual Pricing Option Most Merchants Don’t Know About

There is a fourth option beyond the three pricing models above.

A dual pricing program structures your pricing so that card processing fees are passed transparently to card-paying customers at checkout. Under this model, your effective merchant rate drops to near zero on card transactions, you’re not absorbing the cost at all.

It’s legal in all 50 states, widely used in restaurants, retail, and healthcare, and the fastest-growing pricing structure in small business payments.

It’s not right for every business. But for merchants processing $10,000/month or more, it’s worth understanding the math before deciding.

Getting a Second Opinion on Your Current Structure

Most merchants have never had anyone sit down with them and explain what pricing model they’re on and whether it’s competitive.

PAIR’s free audit does exactly that. We identify your current model, benchmark your effective rate, and tell you plainly whether you’re paying a fair price or leaving money on the table.

The Bottom Line on Pricing Models

Most merchants are on the wrong pricing model simply because no one ever explained the options.

Flat rate works at low volume. Interchange-plus works at moderate volume. Dual pricing works best of all when your business meets the right criteria. A PAIR audit tells you which model fits your situation, and what it would mean financially to change.