Loan Payment Calculator
Enter the loan, the rate, and the term — get your monthly payment, total interest, and payoff date. Then move the extra-payment slider and watch what a few more dollars a month actually does.
Assumes a fixed rate and on-time monthly payments, with any extra applied straight to principal. Taxes, fees, and insurance aren't included.
Juggling several debts, not just one loan? Compare payoff strategies →Ultimate Budget Workbook
A loan payment only works if it fits your month. The budget workbook shows you exactly what fits — and where the extra payment that shortens this loan can come from.
See the Budget Workbook →How loan payments actually work
Every fixed-rate loan — auto, personal, boat, RV — uses the same amortization math. Your payment is fixed, but what's inside it changes every month: at the start it's mostly interest, and by the end it's mostly principal. That's why extra payments early in the loan save so much more than the same dollars later.
The payment formula
Payment = principal × monthly rate ÷ (1 − (1 + monthly rate)−months). The monthly rate is your APR divided by 12. This calculator runs that formula live on your numbers, so you can test a shorter term or a lower rate and see the payment move instantly.
Rate vs. term: the two levers
A lower rate saves interest without changing your payment much; a shorter term raises the payment but cuts total interest dramatically. Comparing a 48-month and a 72-month version of the same loan side by side is usually eye-opening — the longer loan feels cheaper monthly and costs far more overall.
Why extra payments punch above their weight
Every extra dollar skips interest entirely and goes straight to principal. That shrinks the balance interest is charged on for every remaining month of the loan. Even $25–$50 extra per month on a typical auto loan can knock months off the term — the slider above shows your exact number.
How is a monthly loan payment calculated?
Fixed-rate loans use standard amortization: payment = principal × monthly rate ÷ (1 − (1 + monthly rate)^−months). Early payments are mostly interest; later payments are mostly principal. This calculator runs that formula on your numbers and shows the full picture — payment, total interest, and payoff date.
How much does paying extra on a loan actually save?
Every extra dollar goes straight to principal, which shrinks the balance that interest is charged on. Even a small extra monthly payment can cut months off the loan and save a meaningful amount of interest. Move the extra-payment slider to see your exact savings and new payoff date.
Does this work for auto loans, personal loans, and other loans?
Yes — it models any fixed-rate, fixed-term loan with monthly payments: auto loans, personal loans, boat or RV loans, and similar. It doesn't model credit cards (revolving balances) or loans with variable rates.
Is this loan payment calculator free?
Yes — free, no ads, no signup, and it runs entirely in your browser. Nothing you enter is sent anywhere or stored.