Card processing fees: interchange-plus vs a flat rate

Interchange is the fee the card network sets for each type of card, paid to the bank that issued it. A flat rate bundles that and the processor's margin into one price, the same for a basic debit card and a premium rewards card. Interchange-plus passes the interchange through at cost and adds a posted margin. Helcim is the example here because it prints its margin by monthly volume on its own pricing page (2026-11-03):

As printed on helcim.com/pricing, read 2026-11-03. The page shows dollar amounts and does not name the currency or the country; Helcim's US Terms of Service (legal.helcim.com/us, read 2026-11-04) point to this page for its fees. Helcim's own claim, not ours: "near or below 2% in person, below 2.5% keyed and online".

How much is interchange? Visa's U.S. schedule dated April 18, 2026 lists consumer credit rates from 1.33% + 5 cents (the lowest card-not-present row we read) up to 3.15% + 10 cents (its Non-Qualified Consumer Credit category). Where your cards land inside that range decides which pricing wins.

The break-even average interchange rate

This is the average interchange at which interchange-plus costs exactly the same as Stripe's flat rate. If your cards average less than this, interchange-plus is cheaper. It depends on the payment size because the flat rate has a 30-cent fixed part and interchange-plus has a smaller one.

Estimates. Break-even = flat percent minus the margin percent minus the 0.14% assessment, plus the difference in fixed cents (flat fixed minus 10 cents of fixed interchange minus 1.95 cents of network fee minus the margin's fixed cents) divided by the payment size. The 10 cents of fixed interchange is our assumption; Visa's consumer credit rows list 5 to 10 cents. Helcim's first volume tier is used.

Card-brand costs are counted: a 0.14% assessment and a 1.95-cent network fee per credit payment, because interchange-plus passes them on and a flat rate already includes them. Those two figures are republished by Helcim at helcim.com/visa-usa-interchange-rates (read 2026-11-03); Visa's and Mastercard's own assessment documents were not available to us, so treat them as secondary. Left out, the online break-even at a US$400 payment would read 2.39% instead of 2.24%.

The same US$20,000 a month, priced both ways

Estimates: 50 payments of US$400 a month, 600 a year, all one payment type, no tips, international cards or disputes. The three average-interchange levels are scenarios, not a market average. Your processor's statement shows your real average.

Debit cards are where a flat rate costs most

A flat rate charges a debit card the same as a credit card. Federal Reserve rules cap debit interchange from large banks (issuers with $10 billion or more in assets) at 21 cents + 0.05% of the payment, which is US$0.41 on a US$400 payment. With an interchange-plus plan the same payment costs about US$2.66 online or US$2.09 in person with Helcim's first-tier margin, against US$11.90 online or US$10.85 in person at Stripe's flat rates. Small banks and credit unions are exempt from the cap, so their debit cards cost more; the Federal Reserve's 2024 averages were 23 cents + 0.47% of the value for covered issuers and 51 cents + 1.21% for exempt ones (on its average payment of about US$42, not on a US$400 payment). The cap is read from the Federal Reserve's Regulation II pages, updated December 19, 2025.

Not for you if your cards are mostly premium rewards or business cards, where interchange runs high and a flat rate can be cheaper, or you take under a few thousand dollars a month, where the posted margin's fixed cents and any statement minimums matter more than the percent.

Four of the five publish flat rates. Rates read on each provider's own pages on 2026-11-03.

Clover's rates here are from its Retail plans page (clover.com/pricing/retail, read 2026-11-03); Clover's other plan pages carry their own plan names and rates, which we did not compare. That page shows in-person and typed-in rates by retail plan; its online, bank-transfer and dispute rates are not on the pages we read, and plan and hardware prices are not in these numbers. Square's paid plans have a monthly fee that is not in these rates. Square and PayPal list further rates for other uses; PayPal's Venmo and pay-later rates are higher and not shown here.

A year at your volume, online

Estimates: each provider's published percent plus its fixed fee on every payment, at 600 payments a year of US$400, all taken online. Job-software apps run on flat rates in the same range: see Jobber and Housecall Pro.

Not for you if you take most payments by bank transfer. See the next section.

US only. The fee is a small percent, not a percent plus 30 cents.

• Stripe: 0.8%, capped at US$5 a payment.
• Square, by invoice: 1%, US$1 minimum.
• Job software: Jobber 1%, Housecall Pro 1%, Workiz 1%, Kickserv 1%.
• On a US$400 payment, a 0.8% bank transfer costs US$3.20. A card at 2.9% + 30 cents costs US$11.90. Over 600 payments that is US$1,920 against US$7,140.

Not for you if your customers will not pay by bank transfer, or you are in Canada.

A surcharge is a fee you add to a credit card payment to cover the card cost. It is allowed in most states and restricted by the card networks. What we read, on 2026-11-03:

• Visa: the surcharge may not exceed the merchant discount rate for the credit card surcharged or 3%, whichever is lower. Visa debit and prepaid cards cannot be surcharged. Notify your acquirer (your processor's bank) at least 30 days before you start. Visa's surcharging Q&A (PDF) and its regulation page.
• Mastercard: the maximum surcharge cap is 4%, and a surcharge also cannot exceed your merchant discount rate for Mastercard credit. It is not allowed on Debit Mastercard or prepaid. Notify both Mastercard and your acquirer at least 30 days before you start. mastercard.com merchant surcharge rules, read 2026-11-03.
• States that prohibit it: Connecticut, Maine and Massachusetts, in their own statutes (we read each on the legislature's website: Connecticut, Maine, Massachusetts). A discount for paying cash is treated differently from a surcharge in those states; read the statute before you advertise one.
• Oklahoma: Visa's own state summary, as of February 15, 2024, listed Oklahoma as prohibiting surcharges. That has changed: the enrolled text of Oklahoma Senate Bill 677 (read on oklegislature.gov, 2026-11-04) repeals the old ban and provides that a seller may add a surcharge to a credit card, with a notice posted at the point of sale and on the website and read out on phone orders, capped at 2% of the transaction or the actual cost to the seller of processing the card, whichever is less. It takes effect November 1, 2025. We read the enrolled bill, not the codified statute.
• Others: Visa's state summary also says Colorado, Minnesota, New Jersey and New York have requirements. We have not read those statutes, so we cannot tell you what they say. Visa's summary is not a statute.

Not for you if you are in one of the states above, mostly take debit, or cannot show the surcharge as a separate line on the receipt. This is a summary of what the networks and three state statutes say, not legal advice; check your processor's rules and a lawyer before you start.

• Card present or not. Stripe adds 0.5 points when a card number is typed in. Square charges 3.5% + 15 cents for a typed or saved card. Clover lists 3.5% + 10 cents.
• Where the card is from. Stripe adds 1.5 points for international cards.
• Which card it is. On interchange-plus the card type moves your cost (Visa's consumer credit schedule runs from 1.33% to 3.15% before the processor's margin); on a flat rate it does not.
• Disputes. Stripe charges US$15 for each dispute. The Housecall Pro page has its chargeback terms.
• Instant payout. Getting paid today instead of in a day or two costs extra at some providers (Jobber 1%, Housecall Pro 1%, Workiz 1.75%). We did not confirm Stripe's or Helcim's instant payout fee.

What are average credit card processing fees for a small business?

On the published flat rates we read, a US$400 card payment costs about 2.3% to 2.7% of the payment in person and 3.0% to 3.6% online or by invoice, fixed cents included. At US$20,000 a month on cards that is roughly US$6,510 to US$7,140 a year at Stripe's rates. These are published list rates for Stripe, Square, Clover and PayPal, not a survey average, and they exclude typed-in cards, international cards and disputes.

Is interchange-plus cheaper than a flat rate?

Often, but not always. On a US$400 online payment, Stripe's flat 2.9% + 30 cents costs the same as Helcim's posted margin (interchange + 0.50% + 25 cents) when your average interchange is about 2.2%. Below that, interchange-plus costs less; above it, the flat rate does. That calculation assumes 10 cents of fixed interchange; the fixed part is ours to assume, not a published average.

Do I pay the same rate on debit cards as on credit cards?

On a flat rate you do: the plans we read (Stripe, Square, PayPal) list one rate for a card with no lower debit rate. Federal Reserve rules cap debit interchange from large banks at 21 cents + 0.05% of the payment, which is US$0.41 on a US$400 payment, and an interchange-plus plan passes that through plus its own margin.

Can I add a surcharge to credit card payments in the United States?

Often yes, with limits. Visa caps a surcharge at the lower of the card's merchant discount rate or 3%, Mastercard caps it at 4%, neither allows it on debit, and you tell your processor at least 30 days before starting. Connecticut, Maine and Massachusetts prohibit surcharges by statute (we read all three). This is a summary, not legal advice.

We read each provider's own pricing page and dated the day we looked: Stripe, Square, PayPal, Clover and Helcim on 2026-11-03, and the Mastercard, Connecticut, Maine and Massachusetts pages the same day. Visa's interchange schedule (dated April 18, 2026), Visa's surcharging Q&A and the Federal Reserve's Regulation II pages were read by our research pass the same day; the Visa rows we quote are the lowest card-not-present consumer credit row and the highest consumer credit row. The job-software apps come from our fact store, read 2026-10-20 to 2026-11-02, and each is dated on how we check prices. We did not test these payments ourselves.

What we did not confirm: Clover's online, bank-transfer and dispute rates; Stripe's and Helcim's instant payout fees; Mastercard's interchange schedule; the codified Oklahoma statute (we read the enrolled bill); the details of the Colorado, Minnesota, New Jersey and New York rules; and which country Helcim's printed table is for (its page does not say).

Related: what Jobber really costs a crew, what Housecall Pro costs, and which of the two costs less at your invoice size.