Auto Loan Calculator United States
This auto loan calculator estimates your 2026 monthly car payment, total interest and amount financed from price, down payment, trade-in, APR and term.
What it does
The Auto Loan Calculator works out the monthly payment and total interest on a car loan in the US after your down payment and any trade-in, using the price, APR and term you enter.
Data sources & parameters
This calculator uses standard financial formulas and runs entirely in your browser. It needs no external rate data — your result is computed only from the values you enter above.
We always strive to use the latest data for every variable so our results and reports are as accurate as possible. Even so, errors are possible — you should not rely on this tool or its report alone, and we accept no liability for any decision made based on it.
The formula
Amount financed = price − down payment − trade-in; monthly payment = P × i ÷ (1 − (1 + i)^−n), where i is the monthly rate and n the term in months; total interest = payment × n − amount financed
How it works
It subtracts your down payment and trade-in from the vehicle price to get the amount financed, then applies the standard fixed-rate amortization formula over the number of months to find the level monthly payment and the interest paid across the whole loan.
Where it is used
- Comparing loan terms before you sign at the dealership
- Seeing how a bigger down payment cuts the monthly payment
- Estimating the true cost of financing a used or new car
Worked example
A $35,000.00 car with $5,000.00 down at 6.5% over 60 months means financing …, a monthly payment of … and … in total interest.
Most car purchases involve a loan, and at the dealership the monthly payment gets most of the attention. This auto loan calculator takes a vehicle price, down payment, trade-in, interest rate and term and shows the amount you finance, your monthly payment, and the total interest over the life of the loan. Change the inputs to see how each one affects the deal before you sign.
How the calculation works
A car loan uses the same amortization formula as a mortgage. The calculator subtracts your down payment and the value of any trade-in from the vehicle price to get the amount financed, the principal you borrow. It converts your annual percentage rate into a monthly rate by dividing by twelve and spreads the principal over the months in your term so every payment is the same. Early payments are mostly interest and later ones mostly principal, but on a fixed-rate loan the monthly amount does not change.
At a zero rate, sometimes offered as a promotion on new cars, the payment is the amount financed divided by the number of months and there is no interest. At any other rate, total interest is the sum of all payments minus the amount financed.
Why the down payment matters
A down payment reduces the amount financed dollar for dollar, so it cuts both the monthly payment and the total interest. It also improves your loan-to-value ratio, the size of the loan relative to the car’s value. Lenders tend to offer their best rates to borrowers who put more down, and a larger down payment protects you from being underwater (owing more than the car would sell for) in the early years, when new cars lose value fastest. A trade-in works the same way: its value comes straight off the amount financed.
Long loan terms
Loans of 72 or 84 months have become common because they make an expensive car feel affordable each month. You carry the balance, and pay interest on it, for many more months, so total interest climbs sharply. On a moderately priced car, the difference between a five-year and a seven-year loan can be thousands of dollars, and a long term keeps you underwater for longer, which is a problem if the car is totaled or you want to sell. Check the total interest figure before choosing a longer term.
Shopping the interest rate
Apart from the down payment, the APR is the biggest factor you can influence. The rate you qualify for depends on your credit score, the lender, the loan length and whether the vehicle is new or used; used-car loans usually carry higher rates. Getting pre-approved by your bank or a credit union before you visit the dealer gives you a rate to compare against, since dealer financing is convenient but not always the cheapest. Enter a few APRs to see how one percentage point changes the payment and the total cost.
A worked example
Suppose you buy a car priced at $35,000, put $5,000 down with no trade-in, and borrow at 6.5 percent APR over 60 months. The amount financed is $30,000, the monthly payment is about $587, and you pay roughly $5,200 in interest over the loan. Raise the down payment to $8,000 and the amount financed drops to $27,000, lowering both the payment and the interest. Shorten the term to 48 months instead and the monthly payment rises, but total interest falls because you clear the balance sooner.
Assumptions and limitations
This calculator is an estimate for planning and comparison. It models a standard fixed-rate, fully amortizing loan with equal monthly payments and assumes the APR you enter is the true annual rate. It does not include sales tax, title, registration, documentation or other dealer fees, which vary by state and dealership; if you will finance those costs, add them to the vehicle price. It also leaves out gap insurance, extended warranties, manufacturer rebates and variable-rate promotions. Your actual payment and rate depend on your credit and the lender, so treat the result as a starting point, not a quote.
About This Auto Loan Calculator
Use this auto loan calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.
Frequently asked questions
How is my monthly car payment calculated?
What APR should I enter?
Does a longer loan term save me money?
How does a down payment or trade-in change the loan?
Are sales tax and dealer fees included?
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