At the checkout all three look identical: split the price, pay nothing today. The differences show up later — in how often payments leave your account, whether interest is quietly added, and what a missed week costs you.
| Klarna | Afterpay | Affirm | |
|---|---|---|---|
| Typical rhythm | Pay in 4, every 2 weeks; or Pay in 30 | 4 instalments, every 2 weeks | Monthly plans, often longer terms |
| Interest | None on Pay in 4 / Pay in 30; financing plans may charge it | None | Often yes — APR shown at checkout |
| Late fees | Yes, on missed payments | Yes, but capped | No late fees (interest can still accrue) |
| Best at | Flexibility of plan types | Short, predictable splits | Bigger purchases spread monthly |
Fee tables compare the apps. They do not compare the apps against your payday. A two-week rhythm that lands the day after payday is harmless; the same rhythm landing two days before payday is a late fee waiting to happen. If you use more than one of these apps — and most people do — the real question is not which app wins, but whether all their dates together fit the days your money actually arrives.
See all three on one calendar. BNPL Stack Untangler lines up every Klarna, Afterpay and Affirm instalment you have against your payday, flags the tight spots, and gives you one clear payoff date.
The full side-by-side, with each provider's own published terms: Klarna vs Afterpay vs Affirm — the complete comparison.
A companion page for BNPL Stack Untangler — every pay-later plan you have, in one clear calendar.