Every business that takes cards pays to do it — but almost nobody can explain where the money actually goes. Open a merchant statement and you'll find a wall of percentages, per-item fees, and acronyms that seem designed to be un-shoppable.
Here's the thing most sales reps won't spell out: the biggest chunk of your card fees isn't your processor's markup at all. It's interchange — and understanding it is the key to knowing whether you're getting a fair deal.
What interchange actually is
When a customer pays with a card, three companies get a cut:
- The card-issuing bank (the customer's bank) — takes the largest share, called interchange.
- The card network (Visa, Mastercard, etc.) — takes a smaller assessment fee.
- Your processor / merchant services provider — takes their markup for handling the transaction.
Interchange is set by the card networks and is the same for every processor. No one can negotiate it lower for you — not even the big banks. It's the wholesale cost of accepting a card.
Think of it like gas. The pump price is mostly the cost of the fuel (interchange). The station's profit is the small markup on top. Shopping for a "cheaper" processor only changes the markup — not the fuel.
Why one swipe costs more than another
Interchange isn't a single number. There are hundreds of rates, and they shift based on:
- Card type — rewards and business cards cost more (that cash-back is funded by higher interchange).
- How it's run — a physically swiped/tapped card is cheaper than a keyed-in or online "card-not-present" transaction, because it's lower fraud risk.
- Business category — some industries get preferential rates.
- Transaction size — the fixed per-item portion hits small tickets harder.
This is why your effective rate bounces around month to month even when "the rate" on your contract never changed.
The pricing models — and the one to want
Processors package their markup in three main ways:
| Model | How it works | Good or bad? |
|---|---|---|
| Interchange-plus | You pay true interchange + a fixed, disclosed markup | ✅ The transparent one — ask for this |
| Tiered | Transactions sorted into "qualified / mid / non-qualified" buckets | ⚠️ Opaque; easy to hide margin in the buckets |
| Flat-rate | One simple rate for everything (e.g. 2.9% + 30¢) | Simple, predictable, but you overpay on cheap-interchange cards |
Interchange-plus is the model to ask for. Because interchange is a fixed wholesale cost, the only thing you're really shopping is the "plus" — and interchange-plus is the only model that shows it to you plainly. If a processor won't quote it that way, that's a signal.
How to stop overpaying
- Find your effective rate. Take total fees ÷ total card volume for a month. That single percentage is the honest "what am I really paying" number.
- Ask for interchange-plus pricing in writing. Compare the "plus," not the headline rate.
- Watch for junk fees — statement fees, PCI "non-compliance" fees, batch fees, monthly minimums. These are pure markup and often negotiable or waivable.
- Run cards the cheap way — tap/dip in person instead of keying when you can; it lowers interchange.
- Reprice, don't just switch. Sometimes your current processor will match a better offer once you show you understand the model.
The bottom line
Card fees feel like a fixed cost of doing business, and part of them genuinely are — interchange is the same wholesale cost for everyone. But the markup on top is completely shoppable, and the difference between a transparent interchange-plus deal and a padded tiered one adds up to real money every month.
Once you can read your statement, you stop being sold to and start negotiating. The free guide below walks through exactly how card processing works and how to spot what you should — and shouldn't — be paying.