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How auto loans work

An auto loan lets you buy a car now and pay for it over time, plus interest. Here is how the pieces fit together — and how they shape your monthly payment.

The principal

The principal is the amount you actually borrow: the vehicle price, minus your down payment and any trade-in, plus sales tax and certain fees. The larger your down payment and trade-in, the smaller the principal — and the less interest you pay.

Interest and APR

Lenders charge interest for the loan, expressed as an APR. The rate you get depends mostly on your credit score, the loan term, and whether the car is new or used. Even a couple of percentage points makes a big difference over several years.

The term

The term is how long you take to repay, usually 36 to 84 months. A longer term lowers the monthly payment but increases total interest. It is one of the biggest levers on cost — try different terms in the calculator to see.

Amortization: how the payment is built

Auto loans are amortized, meaning each fixed monthly payment covers the interest for that month plus a bit of principal. Early on, more of your payment goes to interest; later, more goes to principal. By the final payment, the balance reaches zero.

Down payment and being "upside down"

A small or zero down payment means you may owe more than the car is worth for a while, especially as new cars depreciate quickly. A healthy down payment protects you from this "negative equity."

Fees and add-ons

Watch for dealer fees, extended warranties and add-ons rolled into the loan — they increase the principal and the interest you pay on it.

General information, not financial advice. Terms vary by lender and state.