Buy Now Pay Later True Cost Calculator
See what an Affirm, Klarna, or Afterpay plan is really costing you — total cost, per-payment amount, and the opportunity cost of the money.
True total cost
$200.00
Same as paying cash
Per payment
$50.00
4 payments over ~8 weeks
Extra vs. cash
$0.00
Only if fees/interest apply
Opportunity cost: if you paid cash and invested $200.00 for a year at 7% instead, it could grow by about $14.00. Splitting a purchase into "4 easy payments" makes it feel smaller than the $200.00 you're actually committing.
The real BNPL danger is losing track
Three or four active plans across different apps, all with their own due dates, is how small payments turn into missed ones. Log every BNPL commitment in ReceiptSync so you always see the full picture.
What buy now pay later really costs
BNPL services make a purchase feel painless by showing "4 payments of $50" instead of $200. On a standard on-time pay-in-4 plan there's no interest, so it truly costs the same as cash — but the moment you add longer-term financing (often 10–36% APR) or miss a payment ($7–$10 each), the real cost climbs. This calculator surfaces that number.
For the full list of BNPL traps — installment framing, stacking multiple plans, invisible total debt, and complicated returns — read our guide to buy now pay later traps with Affirm, Klarna & Afterpay. Trying to keep spending in check overall? Start with the 50/30/20 budget calculator.
This tool is general information, not financial advice.
Frequently asked questions
How much does buy now pay later really cost?
A true 'pay in 4' plan paid on time is 0% interest, so it costs the same as cash. The real cost shows up with longer-term BNPL financing (often 10–36% APR) and with late fees ($7–$10 per missed payment). This calculator adds any interest and fees to show the true total.
Is buy now pay later worse than a credit card?
For someone who pays a credit card in full every month, a rewards card is usually better — you get purchase protection, credit building, and cashback, all of which BNPL lacks. BNPL only comes out ahead if you'd otherwise carry a credit-card balance.
What is the opportunity cost shown here?
It's a rough estimate of what the purchase amount could have earned if invested for one year at a 7% return instead of being spent. It's a clearly labeled assumption to illustrate the trade-off, not a prediction.
Do BNPL late fees really add up?
Yes. Afterpay and others charge around $10 per late payment, capped near 25% of the order. On a small purchase that's a huge effective penalty, and stacking several BNPL plans makes missed payments more likely.
Is this financial advice?
No — it's a free calculator to reveal the true cost of a BNPL plan. Interest is estimated with simple interest over the plan term; your actual agreement governs.