A general-purpose calculator for personal, student, business, and other fixed-rate installment loans. Give it any three of amount, rate, term, and payment and it solves the fourth, then builds a cent-accurate amortization schedule with a payoff date, yearly totals, and the savings from any extra payments you plan to make.
Buying a home or a car? The mortgage calculator adds property tax, insurance, and PMI, and the auto loan calculator handles trade-ins and sales tax. To compare the interest you pay with what savings could earn, see the compound interest calculator. Wondering why early payments barely dent the balance? Why your first mortgage payment is mostly interest walks through the amortization formula behind every schedule this calculator builds.
Quoted an APR rather than a rate? APR vs APY explains why a loan's APR includes fees, and why a longer loan costs more walks through the term trade-off with real numbers.
Frequently asked questions
How is a loan payment calculated?
Most installment loans use the standard amortization formula: payment = P × r ÷ (1 − (1 + r)^−n), where P is the amount borrowed, r is the monthly interest rate (the annual rate divided by 12), and n is the number of monthly payments. Each payment first covers the interest accrued that month, and the rest reduces the balance. Early payments are mostly interest; later ones are mostly principal, which you can see in the schedule. At a 0% rate the formula simply divides the amount by the number of payments. This calculator rounds each month to the cent and adjusts the final payment so the balance ends at exactly zero.
Can I solve for the interest rate, term, or loan amount?
Yes. Leave any one of the four fields blank — amount, rate, term, or monthly payment — and the calculator solves for it from the other three, or tap a Solve for chip to clear that field. The amount and term have exact formulas. The interest rate has no closed-form solution, so it is found numerically by narrowing in on the rate that makes the payment match, which is accurate to well beyond three decimal places. This is handy for checking an offer that only tells you the payment, or for working out how long a fixed budget takes to clear a balance.
Why is the solved term not a whole number of months?
When you solve for the term, a fixed payment rarely divides a balance evenly. A result such as 27.4 months means 27 full payments plus a smaller 28th payment that clears what is left. The schedule shows that last payment exactly, including the interest for that final month. If you pick a whole-number term instead and solve for the payment, the calculator returns the level payment that retires the loan on time, with at most a few cents of rounding absorbed by the final payment.
Does this calculator show APR?
No — it works with the interest rate on the note. APR (annual percentage rate) also includes certain fees, such as origination charges, spread over the loan, so it is usually a little higher than the note rate. To estimate the effect of an upfront fee, you can solve for the rate: enter the amount you actually receive after the fee, the payment, and the term, leave the rate blank, and the result approximates the APR. Lenders in the US must disclose APR on the Truth in Lending disclosure, so compare offers using that figure as well.
How do extra payments change a loan?
Extra money paid toward principal shrinks the balance sooner, so every later month accrues less interest and the loan ends early. Add a recurring monthly amount, a yearly lump sum, or a single payment at a specific payment number and the calculator compares the result with the same loan without extras, showing interest saved and months cut. The required payment does not change; the loan simply finishes sooner. Check that your lender applies extra payments to principal rather than to future installments, and that there is no prepayment penalty, before relying on the savings.