About the Buy Now Pay Later Calculator
This buy now pay later (BNPL) calculator shows what a purchase really costs when you split it into installments. Choose a pay-in-4 plan — four equal payments, the first at checkout and the rest every two weeks, usually at 0% interest — or a longer monthly financing plan with an APR, like the 3- to 36-month loans offered at many online checkouts.
Enter the price, any down payment, the APR and term for monthly plans, and optionally how many payments you might miss and the late fee. You get the installment amount, what is due today, total interest, fees, the total you will pay and how much more that is than the sticker price, plus a full payment schedule.
BNPL can be a useful interest-free way to spread a cost, but monthly plans can carry APRs as high as a credit card and missed payments add fees. Terms vary by provider and by your credit, so use the exact figures from your offer.
With the default inputs, the installment amount is $150.00. Change any value above to recalculate instantly.
How to use the buy now pay later calculator
- 1Enter the purchase price.
- 2Choose Pay in 4 or monthly installments.
- 3For monthly plans, enter the down payment, APR and term from your offer.
- 4Optionally add missed payments and the late fee to see the worst case.
- 5Review the installment, total cost and payment schedule before you check out.
Formula and method
Pay-in-4 plans split the price into four equal payments: one at checkout and three more every two weeks, with no interest if you pay on time. Monthly BNPL loans are simple amortizing loans: the financed amount F is repaid in n equal monthly payments at the monthly rate r (APR ÷ 12), using the standard loan payment formula; at 0% APR the payment is just F ÷ n.
Total interest is M × n − F. Late fees are added per missed payment (providers often cap fees and some charge none), and total cost is price + interest + fees. The calculator assumes no other charges such as account or rescheduling fees.
- F
- Amount financed (price minus down payment)
- r
- Monthly rate = APR ÷ 12 ÷ 100
- n
- Number of monthly payments
- M
- Monthly installment
Worked examples
$600 with Pay in 4
A $600 purchase splits into four $150 payments: $150 at checkout and $150 every two weeks for six weeks. There is no interest if every payment is made on time, so the total is exactly $600.
$1,200 over 12 months at 15.99% APR
Financing $1,200 at 15.99% for 12 months costs $108.87 a month. Over the year that is $1,306.46 in total, so the plan adds about $106 of interest to the price.
$2,000 with $200 down, 24 months at 29.99%, one late payment
After $200 down, $1,800 is financed at 29.99% for 24 months: $100.63 a month and $615 of interest. One $10 late fee brings the total to about $2,625 — over 31% more than the price.
Frequently asked questions
How does Pay in 4 work?+
The price is divided into four equal installments. You pay the first at checkout and the remaining three every two weeks, so the purchase is paid off in six weeks. Most pay-in-4 plans charge no interest, but late fees may apply if a payment fails.
Do buy now pay later plans charge interest?+
Short pay-in-4 plans are usually 0%. Longer monthly plans often charge an APR that can range from 0% to around 36% depending on the retailer, provider and your credit. Always check the APR in the offer before accepting.
Does BNPL affect my credit score?+
Some providers run a soft credit check that does not affect your score. Longer monthly loans may involve a hard check and can be reported to credit bureaus, and missed payments may be reported or sent to collections.
What happens if I miss a BNPL payment?+
You may be charged a late fee, lose access to future BNPL purchases, and on some loans the missed payment can be reported to credit bureaus. Many providers retry the card and cap total late fees.
Is BNPL better than using a credit card?+
A 0% pay-in-4 plan paid on time costs nothing extra, whereas carrying a card balance costs interest. But a card you pay in full each month is also interest-free and may earn rewards. Monthly BNPL loans at high APRs can cost as much as card debt.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.