Auto Loan Calculator
Monthly car payment with sales tax, fees, down payment and trade-in.
Estimate your monthly car payment from the vehicle price, down payment, trade-in, sales tax, fees, APR and loan term — and compare total interest across 36- to 84-month loans.
What you're actually financing
The amount you borrow isn't just the sticker price. This calculator works it out the same way a dealer's finance office does:
- Start with the vehicle price you've negotiated.
- Subtract your down payment and the value of any trade-in.
- Add what you still owe on the trade-in, if anything.
- Add sales tax and fees — title, registration and the dealer's documentation fee — unless you pay them upfront.
Sales tax rates differ by state and often by county or city, so enter the combined rate where you'll register the car. A few states have no sales tax on vehicles at all.
The car payment formula
Auto loans use the same amortization formula as mortgages:
M = P × r × (1 + r)n ÷ ((1 + r)n − 1)
Here P is the amount financed, r is the monthly rate (APR ÷ 12 ÷ 100), and n is the number of monthly payments.
Worked example
Say you buy a $35,000 car with $5,000 down and no trade-in. At 6% sales tax, the tax is $2,100, and fees add another $500. Rolling both into the loan means you finance $32,600. At 7% APR for 60 months:
- Monthly payment: $645.52
- Total interest: $6,131.14
- Total cost of the car, including the down payment: $43,731.14
Shorter vs. longer loans
Here's the same $32,600 at 7% APR over different terms:
| Term | Monthly payment | Total interest |
|---|---|---|
| 36 months | $1,006.59 | $3,637.36 |
| 48 months | $780.65 | $4,871.08 |
| 60 months | $645.52 | $6,131.14 |
| 72 months | $555.80 | $7,417.43 |
| 84 months | $492.02 | $8,729.79 |
Stretching from 60 to 84 months lowers the payment by about $150 a month but adds about $2,600 in interest. In practice, lenders often charge a higher APR on longer loans too, so the real gap is usually bigger.
Ways to lower your car payment
- Get pre-approved by a bank or credit union so you can compare the dealer's financing offer.
- Put more money down. Every dollar you don't borrow saves interest.
- Negotiate the price, not the payment. A low monthly payment can hide a high price or a very long term.
- Pay taxes and fees upfront if you can, so they don't collect interest.
Frequently asked questions
How is a car loan payment calculated?
Lenders use the standard amortization formula: M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), where P is the amount financed, r is the APR divided by 12, and n is the number of monthly payments. Each payment covers that month's interest first, and the rest pays down the balance.
What is a good APR for a car loan?
It depends mostly on your credit score, whether the car is new or used, and the loan term. Borrowers with strong credit get the lowest rates, while used cars and longer terms usually cost more. Compare offers from a bank or credit union before you visit the dealer, so you have a rate to beat.
Is a 72- or 84-month car loan a bad idea?
A longer term lowers the monthly payment but raises the total interest, as the comparison table shows. It also makes it more likely you'll owe more than the car is worth for the first few years, because cars lose value quickly. If you need a long term to afford the payment, consider a less expensive car.
Does a trade-in lower the sales tax?
In most states, sales tax is charged only on the price minus your trade-in value, which can save you hundreds of dollars. A few states tax the full price instead. Check your state's rule and turn off "Trade-in reduces taxable price" if it doesn't apply to you.
What if I still owe money on my trade-in?
Enter that balance in "Amount owed on trade-in." If you owe more than the car is worth (negative equity), the difference is added to your new loan, which raises both your payment and your interest.
Should I roll taxes and fees into the loan?
Paying them upfront means you borrow less and pay less interest. Rolling them in keeps more cash in your pocket today but costs more over the loan. Untick "Include taxes and fees in the loan" to see the difference.
This is an estimate for planning, not a loan offer. Your lender will give you the exact APR, fees and payment before you sign.