How to Calculate a Loan Payment
Published 2026-11-02
Loan calculator searches usually mean one thing: “What will I pay each month?” For a fixed-rate installment loan the answer is the amortization formula — the same math banks teach as PMT.
Use the free tool
Run these formulas with your own numbers. Math stays in your browser.
Open Loan Calculator →Our loan calculator gives payment, total interest and a schedule. The payment calculator adds extra principal and payoff time. The interest-rate calculator reverses the formula when you know the payment and want the APR.
Open the loan calculator
Enter the amount, APR and term in years or months. You will see the monthly payment, total interest and repayment. Switch to the payment calculator if you want to test extra principal.
Monthly payment formula
Convert the annual rate to a monthly rate. Raise one plus that rate to the power of minus n. The last installment is adjusted so the balance lands on zero.
r = APR ÷ 1200
M = P × r ÷ (1 − (1 + r)^−n)
At 0% APR: M = P ÷ n
Worked example
$10,000 at 6% for 36 months: r = 0.005. Payment = $304.22. Total interest is about $951.90 if you pay only the required amount. Month 1 is $50.00 interest and $254.22 principal. The same $10,000 at 6% for 60 months drops the payment and raises total interest — that tradeoff is why “loan calculator” stays a high-volume query next to “mortgage calculator.” Run both terms in the loan calculator before you pick the longer one for a lower bill.
| APR | Monthly payment | Total interest |
|---|---|---|
| 0% | $277.78 | $0 |
| 6% | $304.22 | $951.90 |
| 12% | $332.14 | higher |
Extra principal
Extra principal does not change the bill the lender sends. It reduces the balance faster, so later interest shrinks and the loan can end early. Our payment and amortization calculators apply extra after the required payment. If extra would exceed the remaining balance after interest, the combination is rejected.
- Enter the cash you will actually borrow (fees only if they are financed).
- Enter the APR as an annual percentage.
- Enter months (60 for five years) or years on the loan tool.
- Read payment and total interest.
- Add extra on the payment calculator if you want a shorter payoff.
When another tool is better
Mortgages with tax and insurance belong on the mortgage calculator. A car deal with tax, fees and trade-in belongs on the auto loan calculator. If you know payment and want the implied APR, use the interest-rate calculator. The finance calculator is the signed TVM solver (PV, PMT, FV). A personal-loan search on Google or Bing is usually this formula — amount, rate, months — so start on the loan calculator, then open amortization if you want every row written out.
Use the free tool
Run these formulas with your own numbers. Math stays in your browser.
Open Loan Calculator →Frequently Asked Questions
Does this work at 0% APR?
Yes. The payment is amount divided by months.
Why doesn’t my lender match to the penny?
Rounding, payment dates and day-count conventions differ. Use their disclosure as the contract number.
Can I enter years?
Yes on the loan calculator. The payment tool asks for months.
Are origination fees included?
Only if you add them to the amount financed.
Is this financial advice?
No. It is an estimate for planning.
Related calculators
Loan Calculator
Monthly payment, total interest and total cost of a loan.
Payment Calculator
Monthly loan payment, extra principal and payoff time.
Amortization Calculator
Full monthly and yearly amortization schedule with extra payments.
Interest Rate Calculator
Implied APR from loan amount, payment and term.