Payment Processing · Industry
Ask Affirm what it will charge you and the answer is a form. Ask Afterpay and the answer is a form. Klarna, Sezzle and Sunbit likewise. Every mainstream buy-now-pay-later provider in the United States prices its merchant side in private, which is an odd position for a product sold on the promise of transparency to shoppers.
There is a way round it. The payment processors that resell these products at checkout publish a price list, and because a processor's price is the provider's price plus a margin, the list tells you roughly where the floor is. This article puts the published numbers side by side as of September 2026, sets out what the providers themselves are willing to say, and covers the two things about to change: credit-bureau reporting and the first state licensing regime.
Stripe lists its US buy-now-pay-later methods on its local payment methods pricing page. Affirm is 6% plus 30 cents per successful charge on the standard program and 7.99% plus 30 cents on the enhanced one. Cash App Afterpay is 6% plus 30 cents. Klarna is 5.99% plus 30 cents in the US and Canada. Sunbit, the in-person financing option for auto repair and dental, is 6% plus 30 cents. Zip's pay-in-4 with a customer fee is 4.5% plus 30 cents. Afterpay and Klarna add Stripe's 1.5% for international transactions and 1% for currency conversion; the page also lists the dispute fees, $15 for a lost Klarna dispute and $3 for a lost Zip one, and notes that Stripe may enable Klarna and Affirm for some businesses at a temporary 2.9% plus 30 cents for at least a month before the standard price applies. Stripe's own domestic card rate is 2.9% plus 30 cents.
Square sells one BNPL product, Afterpay, which its parent Block has owned since January 2022. Square's fee page puts Afterpay at 6% plus 30 cents on every channel — in person, online, invoices and virtual terminal — and on every subscription tier, and says there is no monthly fee or start-up cost to enable it. Square's in-person card rate on the free plan is 2.6% plus 15 cents. Sellers are paid the full amount at the time of purchase, minus the fee.
PayPal is the one whose price has visibly moved. Its US merchant fee page, last updated 1 September 2026, lists PayPal Pay Later at 4.99% plus 49 cents, against 3.49% plus 49 cents for ordinary PayPal Checkout. That 4.99% took effect on 13 January 2025; before it, Pay Later was charged at the same 3.49% as a standard PayPal sale. Cross-border transactions add 1.5%.
Shopify routes Shop Pay Installments through Affirm, and its help centre says a merchant is charged "a higher transaction fee" that includes the standard Shopify Payments fee, with the actual rate shown in the store's admin rather than on the public page. It does state the terms that matter operationally: Affirm collects from the customer, you are not at risk if the customer stops paying, you are paid within one to three business days, and disputes run through the same process as Shopify Payments disputes. Shopify's marketing page puts customer rates at 0% to 36% APR.
Set the four side by side and the shape is clear. A BNPL sale through a mainstream processor costs somewhere between 4.5% and 8% plus a fixed 30 to 49 cents, against a card sale at roughly 2.6% to 3.5%. On a $100 order that is $6.30 against $3.20 on Stripe. On a $40 order the fixed fee matters more: $2.70 against $1.46. Twice the cost is a fair rule of thumb, and a little more on small tickets.
Affirm's merchant FAQ is the most candid. It charges "a merchant discount rate (MDR) and transaction fee", set by "the program option you choose, your business size, and your business's risk profile", with no integration, annual or monthly fee. It settles by ACH within one to three business days, pays you "upfront, in full, less the merchant discount rate (MDR) and transaction fee", and says it takes on all repayment risk and never charges shoppers late fees. Shoppers pay between 0% and 36% APR depending on their credit and the program you chose. The line most merchants miss is on refunds: "We don't refund the merchant discount rate or the transaction fee." Affirm's own filings, as our review notes, put blended merchant fees at 2.3% of volume across everything it does, which is a reminder that the 6% Stripe lists is what a small merchant pays for promotional 0% financing, not what a national retailer negotiates.
Afterpay advertises "simple, transparent pricing" and does not print it. Its merchant page says you are paid in one to two business days however the customer checked out, and claims a 58% increase in average order value among merchants that accept it and $8.6 billion of incremental US sales over the preceding twelve months. Both figures are Afterpay's own, from internal data, and should be read as such. Its merchant support documentation, per our review, describes settlement periods assigned per merchant across a one-to-five-day range, which is not the same claim as the marketing page.
Klarna publishes no US rate card at all; its documentation says a fixed fee and a percentage are charged per capture, with the numbers in the merchant portal. Its payout model deserves attention because it is the one that affects working capital: a schedule plus a deliberate payout delay as a buffer against returns, with Klarna's own worked example being weekly Wednesday payouts with a one-week delay. Sezzle says only that a set percentage of each order plus a processing fee applies, with the figures in the agreement you sign, and documents three ancillary charges — a minimum account fee below $300 of monthly volume, a refund fee and an inactive account fee — none with a published amount. Sunbit, which finances service bills at the counter rather than online carts, publishes the same amount about its merchant fee as the rest: nothing.
Zip is the exception that proves the point. Its US business pricing page prints a Standard plan "starting at 5.9% + 30¢ per transaction" with no monthly or annual fee, and a Custom plan for enterprise. Note the phrase: 5.9% is a floor, and it is the highest published headline rate in the category. Note also that it is not the 4.5% Stripe lists — that is a different Zip plan, on which the customer pays a fee.
Splitit sits outside the model entirely. There is no loan and no application: the shopper's existing credit card is authorised for the full amount and charged down in instalments against its own credit line. Because no credit is extended, nobody is declined for credit, and because it runs on the card, it is a card transaction with card rules. Its merchant pricing is quoted rather than published, across tiers whose consumer APR ranges from 0% to 35.99% depending on which side absorbs the cost.
Three things, and it is worth being precise about them because the providers' marketing blurs the first into the other two.
The honest way to run that test is to model it before you switch it on. If your gross margin is 40% and a BNPL sale costs 3.5 points more than a card sale, roughly one BNPL order in eleven has to be a sale that would not otherwise have happened before the fee pays for itself. At a 20% margin it is roughly one in six. The providers' own lift figures are far above either number, which is precisely why you should measure your own.
The published percentage is the part everyone compares. Four other terms decide what BNPL actually costs you, and every one of them lives in the merchant agreement rather than on a pricing page.
For most of its history BNPL was invisible to the bureaus, which is part of why approval rates were high. That is ending. Affirm began furnishing all of its pay-over-time loans, including pay-in-4, to Experian from 1 April 2025; Experian's announcement said the data would not be factored into traditional scores in the near term but would be visible to lenders who request it. Over time this changes who gets approved at your checkout, and the direction is towards fewer marginal approvals rather than more.
At federal level the story reversed in a year. The CFPB issued an interpretive rule in May 2024 treating pay-in-4 accounts as credit cards under Regulation Z; on 6 May 2025 it said it would not prioritise enforcing that rule, and on 12 May 2025 it withdrew it in the Federal Register. New York filled the gap. Its Buy Now, Pay Later Act, Article 14-B of the Banking Law, was signed on 9 May 2025 and requires every BNPL lender operating in the state to be licensed by the Department of Financial Services. DFS circulated a draft for informal comment on 23 February 2026, published its formal proposed rule on 15 July 2026, and is taking comments until 14 September 2026. The law takes effect 180 days after the rule is adopted, with existing lenders given 45 days from that date to apply for a provisional licence.
The substance is aimed at lenders: a 16% cap on interest-bearing BNPL loans, late fees capped at $8 unless DFS approves more, reasonable risk-based underwriting that at minimum assesses income and indebtedness, Regulation Z-style disclosures, a 60-day window for a consumer to dispute a billing error and 90 days for the lender to resolve it, and a bar on adverse credit reporting while a dispute is open. One line touches merchants directly: a seller that agrees a refund must transmit a refund credit statement to the lender within seven business days, and the lender must then credit the consumer within three. If you sell to New York shoppers through a BNPL button, that is a process you will need to have.
None of this is in force yet. The rule is proposed, not adopted, and the 180-day clock has not started. But the providers are already building for it, and merchant agreements tend to be rewritten when the lender's obligations change. Expect a new one.
One last point. The fee is high because the provider is doing two jobs a card network does not: lending to your customer and eating the loss when they do not pay. If you would rather keep the card economics and still offer instalments, the alternative is a product like Splitit that rides on the card the shopper already has — or simply accepting that the customers who most want to pay in four are the ones a card issuer has already declined. How that shows up on your statement afterwards is covered in how to read a merchant processing statement.
