How to use the auto loan calculator
Enter the negotiated price of the car, then the cash you will put down and the value the dealer is giving you for a trade-in. Add your local sales-tax rate and the expected title, registration and documentation fees. Choose whether those taxes and fees are rolled into the loan or paid at signing, then enter the APR and pick a term. The result shows the monthly payment, how much you are actually financing, the interest you will pay and the full cost of owning the car once everything is added up.
How the numbers are worked out
Sales tax is calculated on the price minus the trade-in, which is how most U.S. states handle it (a few tax the full price – check your state). The amount financed is:
The monthly payment then follows the standard amortization formula used for all fixed-rate installment loans, and the yearly table shows how the balance drops over time.
Choosing a loan term
Dealers often advertise low monthly payments by stretching loans to 72 or 84 months. That makes the car feel affordable, but you pay considerably more interest and you may owe more than the car is worth for several years, since vehicles lose value quickly. A 36- to 60-month term usually balances affordability and cost. Try different terms in the calculator to see the trade-off in total interest.
Smart car-buying tips
- Get pre-approved by a bank or credit union before visiting the dealer so you have a rate to beat.
- Negotiate the vehicle price first, then the trade-in, then financing – separately.
- Paying tax and fees upfront avoids paying interest on them.
- A 20% down payment helps you avoid being "upside down" on the loan.
- Remember insurance, fuel and maintenance when deciding what payment you can handle.
Frequently asked questions
Is sales tax charged before or after a trade-in?
In most U.S. states sales tax applies to the price after the trade-in credit, which is what this calculator assumes. Some states tax the full price, so check your local rules.
Should I roll taxes and fees into the car loan?
You can, but you will pay interest on them. Paying them upfront lowers the amount financed and the total interest.
What is a good APR for a car loan?
It depends on your credit score, the loan term and whether the car is new or used. Compare offers from banks, credit unions and the dealer, and enter each APR here to see the difference.
How long should a car loan be?
Many experts suggest no more than 60 months. Longer terms reduce the payment but increase total interest and the risk of owing more than the car is worth.
Last reviewed 2026-10-27. This auto loan calculator is provided for general information; verify important decisions with a qualified professional.