Klarna vs Affirm on Shopify: which should a US store offer?
How each one works for shoppers, how each connects to Shopify in the US, what they cost you, and how to decide for your store.
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Klarna and Affirm side by side
Short answer: Both offer interest-free pay in 4. Beyond that, Klarna adds Pay in 30 days, and Affirm is known for longer monthly plans with interest. The late fee rules differ, and Affirm says it charges none.
| Factor | Klarna | Affirm |
|---|---|---|
| Short-term option | Pay in 4: four payments over about six weeks. Pay in 30 days: pay 30 days after the order ships. | Pay in 4: four interest-free payments every two weeks. |
| Longer plans | Monthly financing, which carries interest and is issued by WebBank. | Monthly plans at 0% to 36% APR, depending on credit. |
| Interest | None on Pay in 4. None on Pay in 30 days if paid on time. | None on Pay in 4. Monthly plans can carry interest. |
| Late fees for the shopper | Pay in 4: up to $7 if a payment is unpaid 10 days after its due date, with total late fees capped at 25% of the purchase. Pay in 30 days: Klarna's page gives no amount, so check the disclosure at checkout. | Affirm says it does not charge late fees. Interest on monthly plans still applies. |
| Credit check | Pay in 4: Klarna may request consumer reports, which its terms say do not leave a hard inquiry. Late or missed payments may still show on a credit report. | A soft check when the shopper applies, which Affirm says does not affect their credit score. Loans may be reported to credit bureaus. |
| Who pays the store | Klarna pays the store and collects from the shopper. Ask for payout timing in writing. | Through Shop Pay Installments, you are paid 1 to 3 business days after capture, minus the fee, and Affirm collects from the shopper. |
| On Shopify in the US | Klarna's Shopify documentation shows Shopify Payments support for the US as expected in 2026, and its Klarna Payments app as not self-serve. | Available through Shop Pay Installments, which needs Shopify Payments and Shop Pay. |
From Klarna's Pay in 4 terms, Klarna's Pay in 30 days page, Affirm's how it works page, Affirm's help on credit, Affirm's business help center and Shopify's Shop Pay Installments pages, checked 13 October 2026. Providers change their terms, so confirm the current US terms before you rely on a figure.
What Shopify supports in the US
Short answer: Affirm reaches US Shopify stores through Shop Pay Installments. Klarna's route is less clear, so check with Klarna and in your admin before you plan around it.
- Affirm through Shop Pay Installments: Shopify offers it to US stores that sell in US dollars and have both Shopify Payments and Shop Pay active. Affirm's 2022 press release describes it as the exclusive partner for the US offer, and Shopify's pages say Affirm is responsible for collecting from your customers. See Shopify's setup page
- Klarna: Klarna's Shopify documentation lists support for the US market in Shopify Payments as expected in 2026, and describes its Klarna Payments app as not self-serve and subject to approval. See Klarna's Shopify page and its integration options
- Shopify Payments methods: Shopify's US page for Shopify Payments lists cards, Apple Pay, Google Pay and Shop Pay. It does not list Klarna or Affirm as local payment methods. See Shopify's US payment methods page
This area changes quickly. Klarna's pages give no update date, so treat our reading of them as correct on 13 October 2026, and check the current position in your own admin and with Klarna. If you need Klarna now, ask Klarna and your payment provider which route they approve for your store.
Shop Pay Installments limits
Short answer: Orders under $35 do not qualify, and the plan a shopper sees depends on the order total.
| Plan through Shop Pay Installments | Order total | Interest |
|---|---|---|
| Two biweekly payments | $35 to $50 | Interest-free |
| Four biweekly payments | $50 to $999.99 | Interest-free |
| Monthly payments over 3, 6, 12, 18 or 24 months | $150 to $30,000 | 0% to 36% APR, where available |
From Shopify's Shop Pay Installments customer experience page. For orders above $20,000 the shopper pays the excess up front and the rest is split into monthly payments. The shopper needs a Shop Pay account and a US billing address.
What it costs you
Short answer: Neither provider publishes a standard US merchant rate we could confirm, so get your fee in writing. Shop Pay Installments orders cost more to process than standard Shopify Payments orders, and the rate shows in your admin.
- Shop Pay Installments: activating it is free. The rate includes the regular Shopify Payments processing fee, and you can see it in Settings, then Payments, under payment rates. You are paid within 1 to 3 business days after capture, minus the fee
- Refunds: the refunded amount comes out of your next available payout. Disputes opened with Affirm appear in your Shopify admin and you answer them as you would other Shopify Payments disputes. See Shopify's getting paid page
- Shopify's third-party fee: Shop Pay Installments is exempt, but a provider added outside Shopify Payments can trigger it. See Shopify's third-party transaction fees page and our guide to Shopify fees
- Klarna: ask for the percentage, any fixed fee, payout timing and refund handling in writing
Work out each fee as a share of your typical order and your margin before you decide. Shopify's pages say merchants are not exposed to losses if shoppers stop paying, because Affirm collects from them.
How to choose
Short answer: Start with what your store can switch on, then look at your typical order size, margins and customers. Run one option, measure it, then decide whether a second is worth the clutter.
- Setup: if you use Shopify Payments and Shop Pay, Shop Pay Installments is the most direct route to Affirm. Klarna depends on the status in your admin and with Klarna
- Order size: your typical order decides which plans appear. Under $35 nothing shows, $50 to $999.99 gets the four-payment plan, and from $150 shoppers can see monthly plans
- Margin: compare the fee on your average order against your margin, using the rate in writing or in your admin
- Customers: look at whether your audience wants a short interest-free split or a longer plan, and note that monthly plans can carry interest
- Support: decide who answers shopper questions about installments, declines and refunds
Our checkout optimization guide covers placement and testing. Our guide to a good conversion rate shows how to measure the result. If you also sell to UK shoppers, read our guide to Klarna vs Clearpay for UK stores, because the options differ there.
Before you switch one on
Short answer: Confirm availability for your store, get fees and payout timing in writing, and test the full checkout and refund flow on a phone.
Pre-launch checklist
- Confirm in your Shopify admin and with the provider that the option is available to your store
- Get the merchant fee, any monthly charge and the payout schedule in writing, or check the rate in your admin
- Check that your typical order falls inside the plan limits
- Place a test order on a phone and complete the payment flow
- Test a full refund and a partial refund
- Update your returns and payment policy pages
- Decide who handles shopper questions and disputes
- Set a review date to compare results with your numbers from before
Frequently asked questions
Is Klarna or Affirm better for a US Shopify store?
It depends on your setup first, because the two do not connect to Shopify in the same way. Affirm is available through Shop Pay Installments if you use Shopify Payments and Shop Pay. Klarna's own documentation shows US support in Shopify Payments as expected in 2026 and its Shopify app as not self-serve, so confirm Klarna's current US status before you plan around it.
Can I add Klarna to my US Shopify store?
Not through a self-serve route as of 13 October 2026, according to Klarna's documentation. Klarna lists Shopify Payments support for the US market as expected in 2026 and says its Klarna Payments app requires prior approval. Check your Shopify admin and ask your Klarna contact, because this can change.
How do I offer Affirm on Shopify in the US?
Use Shop Pay Installments, which Shopify offers for US stores. Your business must be in the US and sell in US dollars, with Shopify Payments and Shop Pay both active. Order totals must fall between $35 and $30,000, including discounts, shipping and taxes.
Does Affirm charge late fees?
Affirm says it does not charge late fees. Monthly plans can still carry interest, and the rate depends on the shopper's credit. Shoppers see their terms before they confirm.
Does Klarna charge late fees?
Yes, it can, and the amount depends on the product. Klarna's Pay in 4 terms list up to $7 per late payment after 10 days, with a cap of 25% of the purchase. Its Pay in 30 days page does not state an amount, so shoppers should check their own disclosure.
Do I pay Shopify's third-party transaction fee on these orders?
Orders paid with Shop Pay Installments are exempt from Shopify's third-party transaction fee. A provider you add outside Shopify Payments, such as a separate app or gateway, can trigger that fee. Our Shopify fees guide explains the rates by plan, and Shopify says Shop Pay Installments orders cost more to process than standard orders, with the rate shown in your admin.
How much do merchants pay for Klarna or Affirm?
Neither provider publishes a standard US merchant rate that we could confirm, so get your fee in writing. Ask about the percentage, any fixed fee per order, payout timing and how refunds are handled. For Shop Pay Installments, Shopify shows the rate under payment rates in your admin.
Will buy now pay later raise my conversion rate?
It can help some stores and not others, so test it on your own store. We do not quote conversion or order value lifts because results depend on your products and customers. Compare conversion rate, average order value, refunds and net margin over the same period before and after you switch it on.
Sources
Checked on 13 October 2026. Providers update their terms, so confirm the current version before you decide. We build only on Shopify and do not offer credit or financial advice.
- Shopify Help Center: Shop Pay Installments, with its setup, customer experience and getting paid pages: eligibility, plan limits, payouts, refunds
- Shopify Help Center: Shopify Payments methods for the US and third-party transaction fees
- Klarna Docs: Shopify and ways to integrate on Shopify: US availability and the Klarna Payments app
- Klarna US: Pay in 4 terms and Pay in 30 days
- Affirm: how it works, Affirm help: credit score and Affirm business help center
- Affirm press release on its Shopify partnership, 2022
