Auto Loan Payment Calculator
Work out your monthly car payment and the total interest you will pay over the loan.
Standard fixed-rate loan formula with optional 2026 state sales tax rates. Last reviewed October 4, 2026. Sources · Methodology
How the auto loan payment is calculated
First the calculator finds the amount you need to borrow:
Amount financed = vehicle price + sales tax + fees − down payment − trade-in value
Sales tax is the tax rate times the vehicle price, or times the price minus the trade-in when the trade-in box is ticked.
That amount is then spread over the term with the fixed-rate loan formula, where r is APR ÷ 12 and n is the number of months:
Payment = P × r(1 + r)n ÷ ((1 + r)n − 1)
Total interest is the sum of all payments minus the amount financed. Total cost of the car is the full vehicle price plus that interest.
Worked example: $35,000 car, $3,000 down, $2,000 trade-in, 7% APR
The amount financed is $30,000. Here is how the term changes the payment and the interest:
| Term | Monthly payment | Total interest |
|---|---|---|
| 48 months | $718.39 | $4,483 |
| 60 months | $594.04 | $5,642 |
| 72 months | $511.47 | $6,826 |
| 84 months | $452.78 | $8,034 |
Moving from 60 to 84 months lowers the payment by $141 but costs $2,391 more in interest.
Sticker price vs out-the-door price
A car is rarely financed at its sticker price. Sales tax and fees are usually rolled into the loan. On a $30,000 car at 7% APR for 60 months with nothing down:
| Financed | Amount | Monthly payment | Total interest |
|---|---|---|---|
| Sticker price only | $30,000 | $594.04 | $5,642 |
| With tax and fees | $33,500 | $663.34 | $6,300 |
Tax and fees add $69 a month here. The state list uses general combined sales tax rates; some states tax vehicles at a different rate, so confirm the rate with your state's motor vehicle agency.
Ways to lower the cost of a car loan
- Get preapproved by a bank or credit union before visiting the dealer, so you have a rate to compare against dealer financing.
- Put more down. Every dollar not borrowed saves interest for the whole term.
- Choose the shortest term you can comfortably afford.
- Negotiate the price, not the payment. A low payment can hide a long term or a high rate.
What this estimate leaves out
- Vehicle-specific tax rules: some states tax cars at a different rate from other goods, cap the tax or charge it on leases differently.
- Insurance, fuel and maintenance. Use the gas cost calculator for fuel.
- Negative equity rolled in from a previous loan.
Frequently asked questions
How is a car payment calculated?
The amount financed is the vehicle price minus your down payment and trade-in value. That amount is repaid in equal monthly installments using the standard loan formula with your APR and term.
Is a longer car loan a good idea?
A longer term lowers the monthly payment but increases total interest, and makes it more likely you owe more than the car is worth for part of the loan. Compare the total cost, not only the payment.
Does this include sales tax and fees?
Yes, when you enter them. Pick your state to fill in its combined state and average local sales tax rate, or type your own rate, and add dealer documentation, title and registration fees. Both are added to the amount financed. They start at zero, so the default result is the sticker-price payment.
Is sales tax charged before or after my trade-in?
Most states tax the price after subtracting the trade-in value, which lowers the tax. A few tax the full price. Untick the trade-in box if your state does not give this credit, and check your state's motor vehicle agency to be sure.
What is the difference between interest rate and APR?
APR includes the interest rate plus certain lender fees, expressed as a yearly rate. It is the better number for comparing loan offers.
Sources
- Consumer Financial Protection Bureau: auto loans
- Tax Foundation: state and local sales tax rates, 2026
- Federal Trade Commission: financing or leasing a car
Last reviewed October 4, 2026. Results are estimates; see our methodology and disclaimer.