GWN Tools · Finance

Auto Loan Calculator

Estimate your monthly car payment, total interest, and total cost from price, tax, down payment, trade-in, and APR.

$
$
$
%
%
months
$0/mo
estimated monthly payment
$0
Amount financed
$0
Total interest
$0
Total cost

Estimates only — not financial advice. Verify with your lender/advisor.

How an auto loan calculator works

An auto loan calculator finds the amount you actually finance — vehicle price plus sales tax, minus your down payment and trade-in — then spreads that amount plus interest evenly across your loan term so you can see the monthly payment, total interest, and total cost before you buy.

How is a monthly car payment calculated?

First the financed amount is found: vehicle price plus sales tax, minus your down payment and trade-in value. Then the payment uses the amortization formula M = L x r x (1 + r)^n / ((1 + r)^n - 1), where L is the financed amount, r is the monthly rate (APR divided by 12), and n is the term in months. Results are estimates, not financial advice.

Is sales tax applied before or after the down payment?

This calculator applies sales tax to the full vehicle price, then subtracts the down payment and trade-in to get the financed amount. Tax rules vary by state, so confirm how your state taxes trade-ins with your dealer or lender.

Does a larger down payment lower my car payment?

Yes. A larger down payment or trade-in reduces the financed amount, which lowers both your monthly payment and the total interest you pay over the life of the loan.