Free planning tool
Auto Loan Calculator
Estimate a car payment from the price, your down payment, a trade-in, sales tax and the interest rate. The same amortization maths as a mortgage, applied over a much shorter term.
Estimate your car payment
Fill in the vehicle details and the amount financed, monthly payment and total interest update as you type.
Estimated monthly payment
$465.92/ month
| Vehicle price | $30,000.00 |
|---|---|
| Sales tax | $2,100.00 |
| Down payment | $5,000.00 |
| Trade-in credit | $3,000.00 |
| Amount financed | $24,100.00 |
| Total interest | $3,855.23 |
| Total paid over the term | $27,955.23 |
Amount financed = price − down payment − trade-in value + sales tax + fees. This calculator applies sales tax to the full vehicle price, before the trade-in credit. Many US states instead tax the price net of the trade-in, which would lower the tax and the payment — check the rule where you are registering the vehicle.
These figures are estimates for planning only. Sales-tax treatment of trade-ins, dealer documentation fees, registration and title costs, gap insurance and dealer add-ons all vary by state and by dealer, and none are modelled beyond the fields shown. Lender rates also depend on credit, term and vehicle age. Only a signed finance offer is a real number.
Using the auto loan calculator
Enter the vehicle and term
Type the agreed price and pick a term between 24 and 84 months, then enter the annual percentage rate you have been offered.
Add your down payment and trade-in
Both reduce the amount you finance. Enter the trade-in figure the dealer has actually agreed, not the private-sale value you hope for.
Check the amount financed
The breakdown shows sales tax as a separate line and the resulting amount financed, so you can see exactly what the monthly payment is being calculated from.
What the calculator covers
The inputs that actually move a car payment, and the assumption behind the tax line.
Down payment and trade-in
Both are subtracted from the amount you finance. Entering them separately shows how much of the reduction is cash out of pocket versus equity in your old vehicle.
Sales tax shown separately
Tax is calculated on the vehicle price before the trade-in credit and listed as its own line, so you can compare it against the figure on a dealer worksheet.
Terms from 24 to 84 months
Longer terms are common on new cars and they reliably lower the payment while raising total interest. Switch terms to see the size of that trade-off on your own numbers.
The same amortization formula
M = P × r ÷ (1 − (1 + r)⁻ⁿ), identical to a mortgage, with r the APR divided by twelve and n the term in months. Car loans and home loans differ in length, not in method.
Zero-percent offers handled
Promotional 0% financing breaks the standard formula, so the calculator detects it and divides the amount financed evenly across the term instead.
Runs in your browser
Nothing you enter about your budget or your trade-in is transmitted or stored. The maths happens in the page.
How the amount financed is built up
The monthly payment is calculated from the amount financed, not the sticker price. That figure is the vehicle price, minus your down payment, minus the trade-in credit, plus sales tax, plus any title and registration fees you choose to roll into the loan.
This matters because two deals with the same headline price can produce quite different payments once tax and fees are included. Working out the amount financed first, and only then applying the interest rate, is also how a dealer worksheet is structured, which makes the two easier to compare line by line.
Sales tax and trade-ins vary by jurisdiction
This calculator applies sales tax to the full vehicle price, before subtracting the trade-in. Many US states instead tax the price net of the trade-in, which reduces the tax due and therefore the payment; a few states charge no vehicle sales tax at all, and some cap the credit.
Because the rule depends on where you register the vehicle rather than where you buy it, check your state before treating the tax line as final. If your state gives a trade-in credit, you can approximate it here by entering a lower tax percentage or by reducing the price by the trade-in before entering it.
What a longer term really costs
Stretching a car loan from 60 to 84 months makes the monthly figure noticeably smaller, which is why long terms are offered so readily. The total interest goes up, and so does the length of time you owe more than the car is worth, because vehicles depreciate fastest early on.
If a payment only works at the longest term available, that is useful information about the price rather than about the financing. Comparing total paid across terms, rather than just the monthly figure, is the quickest way to see what the extra years are buying.
Auto Loan Calculator FAQ
Working out what you can afford overall
A car payment and a housing payment come out of the same budget. Run both, then plan the space you are actually paying for.