Buy now, pay later has become a standard fixture of American online shopping. Major retailers now offer BNPL options alongside credit cards and PayPal as a first-class checkout choice. But the category has matured in a way that makes "just pick whichever one your favorite store offers" less useful advice than it once was — because the differences between the major services now matter, particularly when something doesn't go according to plan. The three dominant US BNPL apps — Klarna, Affirm, and Afterpay — each approach the same basic problem differently, and the right one for you depends on the size of your purchase, your risk tolerance, and how much you want from the app beyond splitting a payment.
At a glance
| Service | Active Users | GMV (latest) | Late Fees? | Max Term |
|---|---|---|---|---|
| Klarna | 118M consumers | $127.9B (FY2025) | Yes (Pay in 4) | Long-term financing |
| Affirm | 23M consumers | $36.7B (FY2025) | No (pay-over-time) | Up to 60 months |
| Afterpay | 24M customers | $8.24B (Q3 2024 GPV) | Yes (capped) | 6 weeks (Pay in 4) |
How we chose
This comparison covers the three BNPL services with the largest confirmed US market presence, based on publicly disclosed consumer and merchant figures from each company's own earnings releases and investor communications. We evaluated each service on: payment structure clarity, fee transparency and risk, credit check practices and approval model, app experience for both checkout and ongoing account management, merchant availability (including reach for non-natively-integrated stores), and in-store payment options. All three are accepted at major US retailers and have sufficiently distinct approaches that the comparison is meaningful. Smaller regional or niche BNPL services are not covered in this comparison.
Klarna: the shopping super-app
Klarna launched its US operations from its Swedish roots and has grown into something more expansive than a payment method. As of its FY2025 annual results, Klarna serves 118 million active consumers and processes $127.9 billion in gross merchandise volume annually across 966,000 merchants globally. Its app reaches more than 55 million monthly active users and handles 3.4 million transactions per day.
Payment options: Pay in 4 (four equal biweekly installments, interest-free when paid on time), Pay in 30 (full balance due in 30 days, interest-free — useful when you want to receive and approve a purchase before technically paying for it), and longer-term financing plans with variable APR for larger purchases that need monthly payment windows beyond six weeks.
Beyond checkout: Klarna's app includes cashback offers at participating brands, price comparison across stores, delivery and returns tracking, loyalty card storage, gift card management, and the Klarna Card for card-based spending with flexible payment options. This breadth makes Klarna the most versatile of the three as a daily-use shopping companion — not just a tool you open at checkout, but one you might use to compare prices before deciding where to buy.
Reach: Klarna's one-time virtual Visa card is usable at any online retailer that accepts Visa, regardless of whether that merchant has a native Klarna integration. This significantly extends Klarna's practical reach beyond its merchant list.
Watch for: Late fees on missed Pay in 4 payments. The one-time card and some premium features may carry costs. The app's feature density can be overwhelming if you want simple installment payments without a full shopping interface. Read the complete Klarna app review for a full breakdown.
Affirm: transparent financing for larger purchases
Affirm was founded in San Francisco in 2012 by Max Levchin, one of PayPal's original co-founders, with the explicit goal of building a more transparent alternative to revolving credit card debt. As of June 2025, Affirm serves 23 million active consumers — up 24% year over year — and 376,800+ active merchants. Its FY2025 GMV was $36.7 billion. A Bankrate survey found 12% of US BNPL users named Affirm as their most-used service, tied with Afterpay.
Payment options: Pay in 4 at 0% APR for qualifying purchases at participating merchants; monthly installment plans from 3 to 60 months with APR ranging from 0% to 36% depending on the specific plan, the merchant's promotional terms, and the buyer's creditworthiness. The 60-month option is the longest available term in the BNPL category and makes Affirm appropriate for genuinely large purchases: furniture, appliances, travel, electronics, where spreading payments over a year or more is the only way the purchase is affordable month-to-month.
No late fees: Affirm does not charge a late fee on pay-over-time plans. If you miss a payment, Affirm will continue attempting to collect, and missed payments may affect your ability to get future Affirm approvals and can be reported to Experian — but there's no penalty charge added on top of what you already owe. For shoppers who are worried about what happens if a payment falls through due to a bank account timing issue, this policy removes the most anxiety-inducing part of BNPL.
Credit reporting: Affirm reports some loan types to Experian, which means responsible use can build credit history, but missed payments can also affect your credit score. This is worth understanding before using Affirm for a large purchase.
Watch for: Interest on longer-term plans can be significant — 36% APR on a 24-month loan adds meaningfully to the total cost. Affirm's approval is per-purchase, so you're re-evaluated at every checkout rather than having a pre-established credit limit. Read the full Affirm app review.
Afterpay: simple Pay in 4
Afterpay was founded in Melbourne, Australia in 2014 and acquired by Block Inc. (Jack Dorsey's company, also owner of Square and Cash App) in 2022. It reported 24 million active customers and 348,000+ global merchants, with $8.24 billion in Q3 2024 gross payments volume — a 23% increase year over year. A Bankrate survey found 12% of US BNPL users named Afterpay as their most-used service, tied with Affirm.
Payment options: Pay in 4 only for the standard product — four equal biweekly installments, with the first payment at the time of purchase. No interest. No complex plan selection. The simplicity is by design: Afterpay's value proposition is the most predictable and easy-to-understand BNPL structure available.
App experience: Clean, focused, and fast to navigate. The merchant directory is a prominent feature — you can browse where Afterpay is accepted before you start shopping, which reduces the friction of discovering at checkout that your preferred provider isn't supported. Approval decisions are fast, and the in-store Afterpay Card (loaded into Apple Pay or Google Pay) provides contactless in-store payment at any NFC terminal.
Watch for: Late fees if a payment is missed — $8 per missed payment or 25% of the order value, whichever is lower, with per-order caps on total late charges. No longer-term financing options, which makes Afterpay less suitable for large purchases you need to spread over many months. Read the full Afterpay app review.
Where each one wins
Klarna — best for shoppers who want the most versatile daily-use app: BNPL plus cashback, price comparison, and delivery tracking in one place. Also the best choice for reaching merchants that don't have native BNPL integration, via the one-time Visa card.
Affirm — best for large planned purchases that need multi-month financing (3 to 60 months), for shoppers who want the reassurance of no late fees on pay-over-time plans, and for those who value clear APR disclosure before committing. The no-late-fee policy is genuinely distinctive and matters for risk-averse shoppers.
Afterpay — best for the simplest possible Pay in 4 experience. Four equal payments, six weeks, always interest-free. If you want to split a purchase without thinking further about it, Afterpay's focused design delivers that with minimal friction and a clear fee structure if something goes wrong.
For a detailed head-to-head comparison, see our Klarna vs Affirm vs Afterpay comparison. For a ground-up explanation of how BNPL works and what consumer protections apply, see our Buy Now, Pay Later explained guide. Our editors' ranked choices are in the best BNPL apps for US shoppers list.
Bottom line
All three services are free if you pay on time. All three are accepted at major US retailers. All three use soft credit checks that don't affect your credit score for the standard Pay in 4 product. The choice between them comes down to three practical questions: How large is the purchase? (Use Affirm if you need more than six weeks.) How much do you worry about a missed payment fee? (Use Affirm if the answer is "very.") Do you want your BNPL app to double as a shopping tool with cashback and price comparison? (Use Klarna if yes.) Everything else is style and preference.
The category has matured to the point where all three services are reliable, well-funded, and legally compliant with US consumer finance regulations. The differentiation is in the details of how each one handles the edge cases: the missed payment, the large purchase, the merchant that's not on the standard list. Understanding those details before you need them is how you choose the right BNPL service for your actual shopping habits rather than whoever happens to appear at checkout first.