Car Loan Calculator
Estimate your monthly car payment, total interest, and total loan cost — including sales tax and trade-in value.
How the car loan calculator works
This calculator uses the standard auto-loan amortization formula that lenders use to set your monthly payment. It first works out your amount financed — the vehicle price, plus sales tax on the price minus your trade-in credit, minus your down payment and trade-in value. That financed amount is then spread across your loan term at your interest rate using the fixed-payment loan formula, so every month you pay the same amount, with more going toward interest early on and more toward principal later.
The formula
Monthly payment = P × [r(1+r)n] ÷ [(1+r)n − 1], where P is the amount financed, r is your monthly interest rate (APR ÷ 12), and n is the number of monthly payments.
Tips for a lower payment
A larger down payment, a shorter loan term, or a higher trade-in value all reduce the amount financed and therefore your monthly payment and total interest. Shopping your interest rate with more than one lender — banks, credit unions, and dealer financing — before you negotiate the vehicle price can also meaningfully lower your total cost, since even a 1–2 percentage point difference in APR adds up over a 60-month loan.
Frequently asked questions
Does this include sales tax?
Yes. Enter your state or local sales tax rate and the calculator applies it to the vehicle price minus your trade-in value, which is how most states calculate tax on a trade-in deal.
Should I include dealer fees?
This calculator focuses on price, tax, and financing. If your dealer quotes documentation, title, or registration fees, add them to the vehicle price field to see their effect on your payment.
Is a longer loan term always worse?
A longer term lowers your monthly payment but increases the total interest you pay over the life of the loan, and it raises the risk of being "upside down" (owing more than the car is worth). Compare total interest, not just the monthly payment, before choosing a term.
What's a good interest rate for a car loan?
Auto loan rates vary by credit score, loan term, and whether the car is new or used. Check current average rates for your credit tier and try a few values in the APR field to see how sensitive your payment is to rate.