Buy Now Pay Later Calculator
The plan, and everything already running
Your result will appear here
Fill in the fields and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States — Truth in Lending disclosure and the CARD Act set the floor; the terms that decide your balance are in your cardholder or loan agreement
- Rules and time period
- APRs, fees, promotional periods and minimum-payment formulas are the ones you enter; an issuer can change several of them with notice.
- Scope and limitations
- Educational estimate only. Your issuer sets the minimum-payment formula, how a payment is allocated across balances, when interest is charged and any fees or promotional terms — check your agreement for the figures that bind, and expect a payoff date to move if a payment is late.
- Source links checked
- Sep 19, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Enter the purchase amount — the full checkout total, including tax and shipping, because the plan is written against what you actually paid rather than the ticket price.
- 02
Check the number of installments and the weeks between them. These two keep their values when the page opens, at four installments two weeks apart, because that is the shape of the standard pay-in-4 plan. Change them for a monthly plan or a longer one, and read the answer to the creditor question below when you do — the number of installments is what decides whether Regulation Z applies at all.
- 03
Enter everything still owing across your other Buy Now Pay Later plans. This is the field that makes the page worth using. No single plan looks like debt; four of them running at once is the thing that catches people out.
- 04
Enter how many payments you expect to miss, honestly, and your provider's late fee. The late fee field opens at $0 and is not assumed, so take the number from your own agreement — they vary widely, and some providers charge none at all.
- 05
Read the 'all BNPL plans together' figure rather than the installment. The installment is designed to look small. The commitment is the number that has to fit in your month.
Formula
Pay-in-4 is arithmetic simple enough to check in your head, which is exactly why it feels harmless. Each installment = purchase amount / number of installments. Late fees = payments missed x late fee. Total you will pay = purchase amount + late fees. All BNPL plans together = purchase amount + other plans still running. There is no interest term anywhere in that, because a standard pay-in-4 plan charges none. The cost of the product, when it goes right, is zero. The cost when it goes wrong is a fixed fee, and a fixed fee on a short loan is a very large rate. That is what the last stat converts: Weeks outstanding = (installments - 1) x weeks between them. With four installments two weeks apart the last payment lands 6 weeks after checkout, not 8, because the first one is taken at the register. Average balance = purchase amount / 2. You start owing the whole amount and finish owing nothing, so across the schedule you hold roughly half of it. Effective annual rate = (late fees / average balance) x (52 / weeks outstanding) x 100. That is a fee expressed as a rate: what share of the money you actually had the use of the fee represents, annualized over how briefly you had it. It is not an APR in the Regulation Z sense and the page does not call it one. It exists so that a $7 charge can be compared with a credit card, which is the alternative most people are actually choosing against. The schedule lists each installment and the balance remaining after it, up to twelve rows. The first row is Week 0 — the payment at checkout.
Example
Inputs: a $600 purchase, four installments two weeks apart, $350 still owing on other plans, no missed payments expected, and the late fee left at $0. Step 1 - The installment. $600 / 4 = $150. That is the headline, and it is the number the checkout page shows you. Step 2 - The schedule. Week 0, $150, leaving $450. Week 2, $150, leaving $300. Week 4, $150, leaving $150. Week 6, $150, leaving $0. The last payment lands six weeks after checkout even though there are four of them, because the first is taken immediately. Step 3 - The total. $600, and the effective annual rate is 0%. Paid on time, the plan is free. The tool says this plainly rather than grudgingly, and then says why it matters: this is exactly what makes it easy to run several at once. Step 4 - The figure that is the actual point. All BNPL plans together: $950. The $600 purchase never looked like debt and the $350 of other plans never looked like debt either, and together they are $950 you are committed to over the next six weeks. The tool calls this out directly — stacked plans are the actual risk with BNPL, because no single one looks large. Now add a single missed payment, with a $7 late fee. The total rises to $607, which sounds trivial. The effective annual rate the tool reports is 20%. Two misses: $614, and 40%. Work through why the small number produces the large one. $7 against an average balance of $300 is 2.33%. But you only held that money for six weeks, and there are roughly 8.67 six-week periods in a year, so annualized it is about 20%. The fee is small because the loan is small and short. The rate is large for exactly the same reason. A $7 fee on a six-week $300 exposure is priced like a credit card, and two of them are priced like a payday product. That is the whole case against treating pay-in-4 as free money. It is free — genuinely, with no asterisk — right up until a payment does not clear, and then the pricing is not gentle. The figure to watch is not $7. It is $950, sitting across four installment dates that do not know about each other and do not know about your rent.
Definitions
- Pay-in-4
- The standard Buy Now Pay Later structure: the purchase split into four equal payments, the first at checkout and the rest every two weeks, with no interest. The four is not arbitrary — it is the line Regulation Z draws, as the creditor entry below explains.
- Installment
- One scheduled payment. The tool divides the purchase evenly, which is how these plans are written; a plan with an uneven first payment or a deposit is a different product and should be entered as the amount actually financed.
- Late fee
- A fixed charge for a payment that does not clear, commonly in the $5 to $10 range with some providers charging none and others capping fees as a share of the order. The cap on credit card penalty fees at 12 CFR 1026.52(b) applies to a credit card account under an open-end consumer credit plan, which a pay-in-4 plan is not, so it does not limit these.
- Stacking
- Running several plans at once across one or more providers. Each is underwritten without full sight of the others, so the total commitment is invisible to everyone including, usually, the borrower. It is the reason this page has a field for other plans.
- Creditor
- Under 12 CFR 1026.2(a)(17)(i) a person who regularly extends consumer credit that is subject to a finance charge or is payable by written agreement in more than four installments, and to whom the obligation is initially payable. A no-interest plan in exactly four installments meets neither test, which is why classic pay-in-4 sits outside most of Regulation Z. Five installments, or any finance charge, changes the answer.
- Effective annual rate
- This page's own conversion of fees into a comparable rate, defined in the formula above. It is not a Regulation Z annual percentage rate and is not disclosed by any provider. Its purpose is comparison with the card you might have used instead.
- Furnishing
- Reporting an account to a consumer reporting agency. The Fair Credit Reporting Act governs the accuracy of what is furnished — 15 U.S.C. 1681s-2(a)(1)(A) prohibits furnishing information a person knows or has reasonable cause to believe is inaccurate — but it does not require anyone to furnish at all, which is why BNPL reporting remains patchy and voluntary.
Frequently asked questions
Is Buy Now Pay Later actually free?
A standard pay-in-4 plan paid on time is genuinely free, with no interest and no fee, and the tool reports a 0% effective rate rather than hunting for a hidden cost that is not there. The provider is paid by the merchant, not by you. Two qualifications. Longer plans — six, twelve, twenty-four installments — frequently do carry interest, and those are a different product wearing the same branding. And the cost of a missed payment is disproportionate: on the defaults a single $7 fee prices out at an effective 20% a year, because the underlying loan is only $300 on average and only lasts six weeks.
Why is a $7 fee an effective 20% a year?
Because rate is a function of amount and time, and both are small here. You owe $600 at the start and $0 at the end, so across the schedule you have the use of about $300. Seven dollars against $300 is 2.33%. The schedule runs six weeks — the last installment lands at week 6, not week 8, because the first payment is taken at checkout — and a year holds roughly 8.67 of those, so 2.33% annualizes to about 20%. Two missed payments double it to 40%. None of this is the provider being predatory in the fee itself; it is what any fixed fee looks like when you express it as a rate on a short, small loan.
Does Regulation Z cover Buy Now Pay Later?
Mostly not, for the classic product, and the reason is a counting rule. 12 CFR 1026.2(a)(17)(i) defines a creditor as a person who regularly extends consumer credit that is subject to a finance charge or is payable by written agreement in more than four installments. A pay-in-4 plan has no finance charge and has exactly four installments, so it clears neither test. Change the plan to five or more installments and the answer flips: the provider becomes a creditor and the plan becomes closed-end credit requiring the disclosures at 12 CFR 1026.18, including an amount financed and an APR. The installments field on this page goes up to 24, so it is entirely possible to model a plan that Regulation Z does cover.
Didn't the CFPB issue a rule making BNPL work like a credit card?
It did, and then it withdrew it. The CFPB published an interpretive rule at 89 FR 47068 on May 31, 2024, 'Use of Digital User Accounts To Access Buy Now, Pay Later Loans', which treated pay-in-4 providers as card issuers subject to the Regulation Z subpart B provisions on billing disputes and refunds. That interpretive rule was withdrawn on May 12, 2025 at 90 FR 20084, where it is listed first among the Interpretive Rules the Bureau withdrew. So the position it set out is not current law and should not be relied on. Anything that tells you a BNPL provider must handle a dispute the way a card issuer does is describing a rule that no longer stands.
What happens if I miss a payment?
It depends entirely on the provider, which is the honest and unsatisfying answer. Some charge nothing. Some charge a flat fee, commonly $5 to $10, sometimes capped at a share of the order. Some retry the card and charge again each time it fails, which is how one missed payment becomes several fees. Some suspend your ability to open new plans. The credit card penalty fee limits at 12 CFR 1026.52(b) apply to a credit card account under an open-end consumer credit plan and so do not reach a pay-in-4 plan. Put your own provider's figure in the late fee field — it opens at $0 precisely so you do not inherit someone else's assumption.
Will BNPL show up on my credit report?
Inconsistently, and asymmetrically. Furnishing is voluntary: the Fair Credit Reporting Act regulates the accuracy of information that is furnished — 15 U.S.C. 1681s-2(a)(1)(A) bars furnishing information the furnisher knows or has reasonable cause to believe is inaccurate — but imposes no duty to furnish in the first place. Several large providers now report some plan types and not others, and the bureaus have been building ways to hold short-term installment data. The practical upshot is the one the tool states: a good repayment record may do nothing for your file, while a default sold to a collection agency can still land on it as a collection account.