Car Loan Calculator

Calculate monthly car payment, total interest and payoff schedule from price, down payment, APR and term, plus interest saved by extra payments.

All calculations happen locally in your browser. Nothing leaves your device.

Monthly payment
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Total interest
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Total repaid
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First vs. last payment
First month
Interest—
Principal—
Last month
Interest—
Principal—

How It Works

The monthly payment uses the fixed-payment amortization formula: M = P × r × (1+r)ⁿ / ((1+r)ⁿ − 1), where P is the amount borrowed, r is the monthly rate (APR ÷ 12 ÷ 100) and n is the number of payments. This yields a constant payment that fully amortizes the loan at the end of the term. Early payments are mostly interest; near the end, almost all of it is principal.

The formula
P is the amount you borrow, r is your APR converted to a monthly rate, and n is the term in months. The fixed payment spreads interest and principal so the balance lands exactly at zero on the last payment. Higher APR or a longer term means a higher payment and more total interest.
Front-loaded interest
Each month interest is charged on the outstanding balance, which is largest at the start. That is why the first payment goes mostly to interest and the last one mostly to principal. If you pay extra early, you shrink the balance that future interest is calculated on — so you save more than you would paying the same extra at the end.
Extra payments
Any amount above the required payment goes straight to principal and shortens the term. Enter an extra monthly amount and the tool simulates the new schedule month by month, showing the months to payoff, the interest you would pay, and the total savings versus the standard schedule.

Frequently Asked Questions

How is the monthly car payment calculated?

The tool uses the standard fixed-payment (equal principal and interest) formula: M = P × r × (1+r)ⁿ / ((1+r)ⁿ − 1), where P is the amount borrowed, r is the monthly rate (APR ÷ 12 ÷ 100) and n is the number of monthly payments. This gives a constant payment that fully amortizes the loan over the term.

Why does the first payment cover mostly interest?

Interest each month is charged on the outstanding balance, which is largest at the start. With a long term and a modest APR, the first month's interest can be a big share of the payment, so most of the principal is paid down near the end. That is why paying extra early saves more interest than paying the same amount later.

What is APR and how does it affect the loan?

APR (annual percentage rate) is the yearly cost of borrowing, including the interest rate and most fees. A higher APR raises every monthly payment and the total interest over the life of the loan; a lower one does the opposite. Term matters too — the same loan at the same APR costs more in total interest over 72 months than over 36.

How much do extra payments save?

Any amount above the required payment is applied straight to principal, which shrinks the balance that generates future interest. The tool simulates this month by month: enter an extra monthly amount and it shows the new payoff time and the total interest you save compared with the standard schedule.

Is my financial data sent to a server?

No. Every number is computed locally in your browser with JavaScript. The page works fully offline once loaded, and nothing you enter is stored or transmitted.