Payment Processing · Buyer guide
Buried on page ten of Visa's US interchange schedule, effective 18 April 2026, is a table most small business owners have never seen and most will never benefit from. It is the Small Merchant Fee Program, and it sets a lower interchange rate on consumer credit cards for any business whose Visa consumer credit sales are $280,000 a year or less. A plain Visa credit card tapped at a qualifying shop costs 1.29% plus 10 cents in interchange; at a larger retailer the same card costs 1.51% plus 10 cents. Online, it is 1.58% plus 10 cents against 1.89%.
That is 0.22 to 0.31 percentage points off the largest component of what a card costs. Whether you ever see it depends on one thing: whether your processor charges you interchange plus a margin, or one flat rate for everything. On interchange-plus, the small merchant rate lands on your statement automatically. On a flat rate, it lands on your processor's. We read the pricing pages of eight processors this site reviews on 19 September 2026 and put one $50 sale through each. Interchange figures are from Visa's schedule; network fees from a 2023 Fiserv pass-through schedule published by the State of North Carolina, the most recent copy of a processor's schedule we could find on a public body's site. If you have not read our guide to reading a processing statement, it explains the three layers — interchange, network fees, processor margin — that this piece adds up.
All figures are Visa's, effective 18 April 2026, for a US consumer card. 'Product 2' is Visa's name for its card-present consumer credit programme and 'Product 1' for card-not-present. 'All Other Products' means a card with no rewards tier.
On top of interchange sit the network's own fees. Fiserv's 2023 pass-through schedule lists Visa's assessment at 0.14% on credit and 0.13% on debit, and an acquirer processing fee of 1.95 cents per credit authorisation and 1.55 cents per debit. Call it 9 cents on a $50 credit sale and 8 cents on debit; there are smaller items, and the individual amounts have moved since 2023, but the order of magnitude has not. So a $50 plain credit card tapped at a small merchant costs about 84 cents before the processor adds anything; the same card at a large merchant about 95 cents; a regulated debit card about 32 cents.
Interchange-plus first. All figures are the published entry-tier prices for a US business.
Now the flat rates, which charge the same whatever the card.
Put the $50 plain credit card tapped side by side: about $1.12 at Helcim, 92 cents plus subscription at Stax, $1.24 at PayPal, $1.40 at Stripe, Shopify and Square Plus, $1.45 at Square's free plan. Against Square's free plan the gap is 33 cents; against PayPal's in-person rate, 12. Eleven cents of it is the small merchant interchange the flat-rate processor keeps; the rest is margin. Online, the same card: $1.48 at Helcim against $1.75 at Stripe, Shopify and Square's API, $1.94 at PayPal, $1.95 on Square's free plan.
Now change the card. A regulated debit card tapped costs about 60 cents at Helcim and $1.45 at Square's free plan: an 85-cent gap on a $50 sale, because the flat rate charges 2.6% for a card whose interchange is capped by federal rule at 0.05% plus 21 cents. A Visa Signature Preferred card tapped costs about $1.41 at Helcim and $1.45 at Square: four cents, which is nothing. The flat rate is priced roughly at the cost of a premium card. Every card cheaper than that is where the flat-rate processor makes its money, and debit is the cheapest card there is.
Scale it. Two hundred $50 sales a month, $10,000, all on plain credit cards tapped at a small merchant: about $223 at Helcim, $282 at Stax on the $99 subscription, $247 at PayPal, $280 at Stripe, $290 at Square's free plan. Helcim beats the flat rates by $24 to $67 a month; Stax does not beat them at all, because 200 transactions do not earn back $99. At six hundred sales, $30,000 a month: about $669 at Helcim, $748 at Stax — which is now on its '$199+' tier because $30,000 a month is $360,000 a year — $840 at Stripe, $870 at Square. The flat-rate premium is now $170 to $200 a month on a mix that flatters the flat rate. Make half the cards regulated debit and the gap grows by about three-quarters.
Between the two interchange-plus models the crossover is about ticket size, not volume. Helcim's margin on a $50 tapped sale is 28 cents; Stax's is 8 cents; the 20-cent saving needs 495 transactions a month to cover a $99 subscription, or about $24,750 of sales. On a $200 ticket Helcim's margin is 88 cents against the same 8 cents, an 80-cent saving, and the subscription is covered at 124 transactions. Stax's model is built for businesses with large tickets; at small tickets and modest volume Helcim's no-fee model wins, and below a few thousand dollars a month the flat rates are close enough that simplicity is worth the difference.
Between interchange-plus and flat rate, the crossover is about card mix, and it is lower than most guides say. On plain credit alone the flat rates cost a small merchant 12 to 33 cents more per $50 sale, up to about $800 a year at $10,000 a month. Add a normal share of debit and it is more. The reason the flat-rate processors can hold an A grade on this site anyway is everything else they bundle — free software, next-day deposits, no monthly fee, no contract — which is worth real money to a business at $3,000 a month and progressively less to one at $30,000.
Find out which model you are on; the statement says. If it is a flat rate, pull three months of sales and estimate your debit share — if it is above a third, you are almost certainly overpaying and an interchange-plus quote is worth an afternoon. If it is interchange-plus, look for 'Small Merchant' in the interchange lines; if you are under $280,000 in Visa credit sales and it is not there, ask why. And if you are choosing today at under a few thousand dollars a month, the flat rates are not a mistake. They are a convenience fee of roughly 12 to 85 cents per $50 sale, depending on the card, and you should know that is what you are paying for.
