When Flat-Rate Card Processing Stops Making Sense

How flat-rate pricing makes money

A flat-rate processor charges one price for every card. Stripe, for example, publishes 2.7% plus 5 cents for in-person card payments in the U.S. and 2.9% plus 30 cents for online card payments, and other flat-rate providers publish similar figures.

Behind that single price, the processor still pays interchange that varies from card to card. It earns a wide margin on low-cost cards and a thin one on premium rewards cards. Across all its merchants, the averages work out in its favor.

For a small business just getting started, that trade is often a good one. The question is when it stops being a good one for you.

The debit card problem

Debit cards issued by banks with $10 billion or more in assets carry interchange capped by the Federal Reserve at 21 cents plus 0.05%, plus a one cent fraud-prevention adjustment. On a $40 sale, that is about 24 cents.

If you run 500 debit sales a month at that ticket size, the difference is about $445 a month on debit alone. Interchange-plus pricing passes the low debit cost through and adds only your markup.

A break-even worksheet

To compare fairly, price the same month both ways. The example below assumes:

• An average ticket of $40.
• 45% of volume on large-bank debit cards and 55% on credit cards, with credit interchange averaging about 1.80% plus 10 cents.
• Network fees of about 0.14% of volume.
• An interchange-plus markup of 0.30% plus 10 cents, with $45 a month in account and compliance fees.
• A flat rate of 2.7% plus 5 cents with no monthly fee.

Under these assumptions, interchange-plus costs about 2.09% of volume plus $45 a month, and the flat rate costs about 2.83% of volume.

The break-even point in this example is about $6,100 a month. Above it, every additional dollar of sales widens the gap. At $40,000 a month the difference is $3,000 a year.

Your break-even point will differ. A higher average ticket, a larger debit share, or lower monthly fees on the interchange-plus account pulls it down. A smaller ticket, mostly premium credit cards, or higher monthly fees pushes it up.

Run it with your own numbers

1. From your last three statements, total your card sales and transaction count, and calculate your average ticket.
2. Find your debit share from the card-type breakdown, if your processor shows one.
3. Ask for a written interchange-plus quote that lists the markup and every monthly fee.
4. Estimate interchange using the published Visa rates in our guide to interchange fees, or ask the quoting processor to price your actual statements.
5. Compare the monthly totals instead of the headline rates.

Calculating your effective rate lists what belongs in each total.

When flat-rate pricing is still the right choice

• Low or irregular volume. Under a few thousand dollars a month, monthly fees on an interchange-plus account can wipe out the savings.
• Seasonal businesses with long quiet months.
• New businesses that need to start taking cards quickly while they build a processing history.
• Businesses that rely on bundled software, where the processing price pays for point-of-sale, invoicing, or online store tools you would otherwise buy separately.

Costs to check before switching

Flat-rate platforms often tie processing to their own software and hardware. Before switching, check whether your point-of-sale system works with another processor, whether you lose features like instant payouts or invoicing, and whether your terminals can move. Some businesses keep their software and change only the processing. Others find the bundled tools worth the higher rate.

If you decide to move, our comparison of interchange-plus, tiered, and flat-rate pricing explains what to look for in the new quote, and why tiered pricing is the one to avoid.