Swipe a customer's card for $100, and you will not deposit $100. Somewhere between $1.50 and $3.50 quietly disappears before the money ever reaches your bank account — and most small business owners have no idea where it went, only that their processor's statement is nearly impossible to read.
That opacity is not an accident. Card processing is one of the few line items on a small business's P&L where the seller has almost no visibility into what they're actually being charged, let alone why. But a meaningful chunk of that fee is negotiable, and knowing which chunk is the difference between overpaying by a few hundred dollars a year and overpaying by a few thousand.
The Anatomy of a Swipe: Interchange vs. Markup
Every card transaction is actually three fees stacked together, and only one of them is up for negotiation.
Interchange fees go to the bank that issued the customer's card (Chase, Capital One, your local credit union). They're set by the card networks — Visa, Mastercard, Discover, American Express — based on the card type, how it's rewards-tiered, and how the transaction was processed (chip-and-PIN in person, keyed-in over the phone, or card-not-present online). A rewards credit card typically costs more in interchange than a plain debit card, because the issuing bank is funding those points and cashback out of that fee. Every processor in the country pays the same interchange rate for the same transaction — this part of the bill is fixed, no matter who you sign with.
Assessment fees go to the card network itself (Visa, Mastercard, etc.) for using their rails. These are also small, fixed, and non-negotiable — typically a fraction of a percent.
Markup is what your processor adds on top of interchange and assessments to make a profit. This is the only piece of the fee stack that varies from provider to provider, and the only piece you can actually negotiate down.
The problem is that most pricing models are deliberately built to hide where interchange ends and markup begins.
The Four Pricing Models, Decoded
Flat-rate pricing (think Square, Stripe, PayPal) charges one blended percentage — commonly around 2.6%–2.9% plus a small per-transaction fee — regardless of card type. It's simple and predictable, which is exactly why it's popular with new and low-volume businesses. But you're paying a single rate on every card, including debit cards that carry much lower interchange — meaning the processor pockets a bigger markup on your cheapest transactions.
Tiered pricing buckets transactions into "qualified," "mid-qualified," and "non-qualified" categories, with wildly different rates for each. Processors control which tier a given card lands in, and the criteria are rarely disclosed — it's one of the most common ways small merchants get quietly overcharged.
Interchange-plus pricing shows the actual interchange rate for each transaction plus a fixed, contractually locked markup (e.g., interchange + 0.30% + $0.10). It's more complex to read, but it's the only model where you can see exactly what the bank took and exactly what your processor took — and the markup can't move without your signature.
Subscription (membership) pricing charges a flat monthly fee for near-cost access to interchange rates, plus a small per-transaction fee. It rewards high volume, since the fixed subscription cost gets diluted across more transactions.
Which one actually saves you money? It comes down to volume and average ticket size. Below roughly $8,000–$10,000 in monthly card volume, flat-rate pricing is often just as cheap as anything else, and far simpler to manage. Above that threshold, interchange-plus or subscription pricing typically wins — on $30,000 in monthly volume, the gap between a 2.9% flat rate and a well-negotiated interchange-plus deal can run $200–$400 a month, or several thousand dollars a year.
The Fees That Have Nothing to Do With Interchange
Beyond the per-transaction rate, watch your monthly statement for charges that are pure processor profit and often negotiable to zero:
- PCI compliance fees — a recurring charge, often $10–$25/month, that processors bill to help you complete the annual Self-Assessment Questionnaire required to stay PCI-DSS compliant. This is different from a PCI non-compliance fee ($20–$100+/month), which is a penalty for not completing that questionnaire at all — don't confuse paying the first with being excused from doing the actual work.
- Statement and batch fees — small recurring charges just for having an account or for closing out each day's transactions.
- Monthly minimum fees — a penalty charged when your processing volume falls below a threshold the processor set.
- Early termination fees — the cost of leaving a multi-year contract, which is exactly why you should never sign one without reading the cancellation terms first.
None of these have anything to do with interchange. They're pure margin, and they're usually the first thing that comes off the table when you call and ask.
Four Ways to Actually Lower the Bill
- Get an itemized quote from at least two competing processors and ask specifically for interchange-plus pricing with the markup spelled out in basis points. A processor unwilling to disclose their markup structure is telling you something.
- Cut your chargeback rate. Chip and contactless (tap-to-pay) transactions shift fraud liability away from the merchant and often qualify for lower interchange tiers than a manually keyed card number. Keyed and card-not-present transactions are the most expensive category — for good reason, they're the riskiest.
- Eliminate junk fees before negotiating rate. A statement fee or PCI fee is easier to get waived in a five-minute call than a full repricing, and it's pure savings either way.
- Consider surcharging or cash discounting — but only after checking your state's rules.
Surcharging and Cash Discounts: What's Actually Legal in 2026
Passing card costs to the customer is legal in most of the country, but the rules are specific and the two approaches are not interchangeable:
- Cash discounts are legal in all 50 states. You post one higher list price that bakes in processing cost, then discount it at checkout for customers paying cash or debit.
- Surcharges add a fee at checkout only for credit card payments, on top of the listed price. As of 2026, Connecticut, Massachusetts, Maine, and Puerto Rico still ban outright surcharging.
- Network caps apply regardless of state law: Visa limits surcharges to 3% of the transaction; Mastercard allows up to 4%. Since most processors can't split networks out at checkout, 3% is the practical ceiling if you accept Visa at all.
- Debit cards can never be surcharged, even when processed through a credit network — this is federal law under the Durbin Amendment, not a state-by-state variable.
- Disclosure is mandatory: clear signage at the entrance and point of sale, the surcharge shown before the customer confirms payment online, and the fee itemized as its own line on every receipt.
Get any of this wrong and you risk a card network fine, not just an unhappy customer — so confirm your state and processor's specific rules before turning surcharging on.
Don't Let Fee Confusion Bleed Into Your Books
Processing fees create a bookkeeping trap that's easy to miss: your processor doesn't deposit your gross sales, it deposits sales net of fees. If you record only the deposit amount as revenue, you've quietly understated both your sales and your expenses — which distorts your margins and makes it harder to spot when a processor's rate creeps up. The cleaner approach is to record the full sale amount as revenue and the fee as a separate expense line, so the two numbers stay visible and comparable month over month.
This is exactly the kind of detail that's easy to lose in a black-box accounting tool but straightforward to track when your books are plain text. With Beancount.io, you can post the gross sale, the processing fee, and the net deposit as three explicit legs of the same transaction — giving you a clear, version-controlled, auditable trail of exactly what each processor is costing you over time, without vendor lock-in. Get started for free and see why developers and finance-savvy business owners are switching to plain-text accounting.