Auto Loan Calculator

Estimate your monthly car payment including down payment, trade-in value, sales tax and dealer fees.

  • Reviewed October 2026
  • Formula and worked example below
  • Free, no sign-up, runs in your browser
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Enter your numbers to see the result.

How your car payment is worked out

The amount you finance is the vehicle price plus sales tax and fees, minus your down payment and trade-in. That amount is then repaid in equal monthly installments using the standard loan formula. In most US states sales tax applies only to the price after the trade-in credit, which this calculator assumes.

Financed = Price + Tax + Fees − Down payment − Trade-in

Example

A $35,000 car with $5,000 down, 7% sales tax ($2,450) and $800 in fees means financing $33,250. At 7.5% APR for 60 months the payment is $666.28, and you pay about $6,727 in interest over the loan.

The 20/4/10 guideline

A widely used rule for car buying: put at least 20% down, finance for no more than 4 years, and keep total car costs (payment, insurance and fuel) under 10% of gross income. Longer 72- and 84-month loans lower the payment but raise total interest and make it more likely you will owe more than the car is worth.

Tips for a better auto loan

  • 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, separately from financing and your trade-in.
  • Watch for add-ons rolled into the loan, such as extended warranties and paint protection.
  • Manufacturer 0% or low-APR deals sometimes replace a cash rebate; compare both options with this calculator.

Frequently asked questions

Is sales tax included in a car loan?

Usually yes. Most buyers roll sales tax and registration fees into the amount financed, which this calculator does. You can also pay them up front by adding them to your down payment.

What is a good APR for a car loan?

It depends on your credit score and the car's age. Borrowers with excellent credit often get new-car rates several points lower than those with fair credit, and used-car rates are typically higher than new.

How long should a car loan be?

Shorter is cheaper. A 48- or 60-month term balances a manageable payment with reasonable total interest; 84-month loans are best avoided.

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Last reviewed Oct 20, 2026. Results are estimates; check important decisions with a qualified professional.