Auto Loan Calculator
Calculate your monthly car payment, total interest, and total cost for any auto loan — new or used.
What is an auto loan calculator?
An auto loan calculator shows what a car will actually cost per month once you finance it: the Amount financed after your down payment, trade-in and sales tax, the Monthly payment at your APR and term, the Total interest, and the Total of payments over the life of the loan. Enter your numbers above and every figure updates at once.
Run it before you visit the dealership. A longer term can make an expensive car look affordable while adding thousands in interest; knowing your own numbers keeps the conversation on price, rate and term rather than on the monthly payment alone.
The same car, five loan terms
A $35,000 car with $5,000 down and 6.5% sales tax leaves $32,275 to finance. At 7.5% APR:
| Term | Monthly payment | Total interest | Total paid |
|---|---|---|---|
| 36 months | $1,003.95 | $3,867 | $36,142 |
| 48 months | $780.37 | $5,183 | $37,458 |
| 60 months | $646.72 | $6,528 | $38,803 |
| 72 months | $558.04 | $7,904 | $40,179 |
| 84 months | $495.04 | $9,309 | $41,584 |
Stretching from 48 to 84 months cuts the payment by $285 but costs $4,126 more in interest — and leaves you paying for a car that is seven years old at the end. Long loans also keep you "underwater" (owing more than the car is worth) for longer, which matters if it is totaled or you need to sell.
How the APR changes the payment
Lenders set the rate from your credit scores and history, income and debts, the loan's size and length, the down payment and the vehicle, including whether it is new or used (CFPB). For reference, the Federal Reserve reported an average 7.54% on 60-month new-car loans at commercial banks for August 2026. The same $32,275, 60-month loan at different APRs:
| APR | Monthly payment | Total interest |
|---|---|---|
| 0% | $537.92 | $0 |
| 4% | $594.39 | $3,389 |
| 6% | $623.97 | $5,163 |
| 7.54% | $647.34 | $6,565 |
| 10% | $685.75 | $8,870 |
| 14% | $750.98 | $12,784 |
| 20% | $855.09 | $19,030 |
The gap between 6% and 14% on this loan is $127 a month and more than $7,600 of interest over five years — often more than a dealer discount is worth.
How much car can you afford? The 20/4/10 rule of thumb
A widely quoted rule of thumb: put 20% down, finance for no more than 4 years, and keep total car costs (payment, insurance and fuel) under 10% of gross income. On the $35,000 example that means $7,000 down, a 48-month loan and a payment of $732.02 — which on its own takes 10% of a gross income of about $88,000, before insurance and fuel. It is a guideline, not a lending rule; if the numbers do not fit, it points to a cheaper car rather than a longer loan.
Down payment, trade-in and sales tax
A down payment reduces the loan and the interest, and keeps you from being underwater early on. A trade-in works like a down payment, and in many states it also lowers the sales tax, because tax is charged on the price minus the trade-in. On the example, trading in a $5,000 car saves $325 in tax as well as reducing the loan, and the payment drops to $540.02. Not every state works this way: California and Virginia, for example, tax the full selling price even when you trade in a car. This calculator always applies the trade-in credit to the tax, so in those states enter the trade-in value under Down payment instead and leave Trade-in value at 0 — the example then finances $27,275 at $546.54 a month.
Dealer financing vs. your own pre-approval
Get a pre-approval from your bank or credit union before you shop. It tells you the rate you qualify for, caps what you can spend, and gives the dealer a rate to beat; the CFPB notes that dealers can profit by offering a higher rate than the one they receive from the lender. If a manufacturer offers a choice between a low promotional rate and a cash rebate, run both through the calculator and compare the Total of payments.
Formula
Amount financed = price + (price − trade-in) × sales tax rate − down payment − trade-in
Sales tax is applied to the price net of the trade-in, which is how many states tax vehicle purchases. Then the monthly payment uses the standard amortization formula:
Payment = P × r × (1 + r)n ÷ ((1 + r)n − 1)
- P = amount financed
- r = monthly rate = APR ÷ 12 ÷ 100
- n = number of monthly payments
Total paid = payment × n; total interest = total paid − P. At 0% APR the payment is simply P ÷ n and the total interest is exactly $0.00. A negative price, down payment, trade-in, sales tax or APR gives no result, and so does a down payment and trade-in that cover the whole price plus the sales tax. Dealer fees (documentation, title, registration) are not included — add them to the price if they are being financed.
Worked example
A $35,000 car, $5,000 down, no trade-in, 6.5% sales tax, 7.5% APR, 60 months:
- Sales tax: 35,000 × 6.5% = $2,275
- Amount financed: 35,000 + 2,275 − 5,000 = $32,275
- Monthly rate: 7.5 ÷ 12 ÷ 100 = 0.00625; n = 60
- Payment = 32,275 × 0.00625 × 1.0062560 ÷ (1.0062560 − 1) = $646.72
- Total paid = 646.72 × 60 = $38,803; total interest = $6,528
With a $5,000 trade-in in addition to the $5,000 cash: tax is charged on $30,000 ($1,950), the amount financed is $26,950, and the payment falls to $540.02.
After two years
Working the schedule month by month, twenty-four payments into the 60-month loan the balance is about $20,800. On the 72-month version of the same loan it is about $23,100, and on the 84-month version about $24,700 — the longer the term, the more you still owe while the car keeps aging. Compare those figures with what the car would sell for to see whether you would be underwater.
How to use this calculator
- Enter the negotiated price of the car, before tax (add dealer fees here if they will be financed).
- Enter your cash down payment and the value of any trade-in.
- Enter your state's vehicle sales tax rate. Many states charge it on the price after the trade-in credit.
- Enter the APR you have been quoted or pre-approved for, and the loan term in months.
- Read the Monthly payment, Amount financed, Total interest and Total of payments.
What this calculator does not do
- It does not add dealer documentation fees, title, registration, add-ons or GAP coverage unless you include them in the price.
- It always credits the trade-in against sales tax; in states that tax the full price, enter the trade-in as a down payment instead.
- It does not handle a trade-in you still owe money on (negative equity), rebates as a separate input, or local tax rules.
- It does not show the balance after a given number of payments or model extra payments.
Questions to settle before you sign
- Price first, then financing. Agree the price of the car before discussing payments, trade-in or financing — mixing them makes it easy to move money between columns.
- Is there a prepayment penalty? Check the contract; without one, paying extra shortens the loan and saves interest.
- Do you need GAP coverage? If you owe more than the car is worth, gap coverage pays the difference if it is totaled. Compare the price from your own insurer with the dealer's.
- Add-ons — extended warranties, paint protection and similar extras rolled into the loan are financed at your APR. Decide on each one separately.
Related tools
- Sales tax calculator — the tax on the purchase
- How auto loan APR works — rate, APR and what changes them
- Savings goal calculator — saving a down payment, or the whole car, by a date
- Paycheck calculator — your take-home pay
Sources
- Federal Reserve — G.19 Consumer Credit (60-month new-car loan rate at commercial banks, August 2026)
- Consumer Financial Protection Bureau — How does a lender decide what interest rate to offer me on an auto loan?
- Consumer Financial Protection Bureau — How will shopping for an auto loan affect my credit?
- Virginia DMV — Motor Vehicle Sales and Use Tax
Frequently asked questions
How much should I put down on a car?
A common rule of thumb is 20% on a new car and at least 10% on a used one. A larger down payment means a smaller loan, less interest and less chance of owing more than the car is worth. On a $35,000 car, 20% is $7,000; on the example loan, every extra $1,000 down saves about $202 in interest over five years at 7.5%.
Is a longer loan term a good idea?
Rarely. A 72- or 84-month loan lowers the payment but raises the total cost — on the example above, $2,721 more interest than a 48-month loan at 72 months and $4,126 more at 84 months — and keeps you underwater for longer, which hurts if the car is totaled or you need to trade it in. If the payment only fits with a very long term, consider a cheaper car.
Does the calculator include taxes and fees?
It includes sales tax, applied to the price net of any trade-in. It does not include dealer documentation fees, title, registration or add-ons; enter them as part of the price if they are being financed. In states that tax the full price despite a trade-in, such as California and Virginia, enter the trade-in under Down payment so the tax is figured on the full price.
Should I get pre-approved before going to the dealership?
Yes. A pre-approval shows the rate you qualify for, sets a budget, and turns dealer financing into a bid to beat. Shopping around has limited effect on your credit: according to the CFPB, auto-loan inquiries made within 14 to 45 days of each other generally count as a single inquiry, depending on the scoring model.
How does my credit score affect the rate?
Credit scores and history are one of the factors lenders use, alongside your income and debts, the size and length of the loan, the down payment and the vehicle. A lower score usually means a higher APR, and the table above shows what that does: the same loan costs $623.97 a month at 6% and $750.98 at 14%. If a promotional manufacturer rate is advertised, ask what credit score it requires.
New or used: how do I compare the cost?
Run each car with its own price and the rate you are offered for it, since lenders price new and used vehicles differently. With $5,000 down and 6.5% tax, a $35,000 new car at 6.5% for 60 months costs $631.50 a month ($37,890 in total payments); a $25,000 used car at 9% costs $448.90 a month ($26,934). Then weigh the difference against age, warranty and expected repairs.
Can I pay off my car loan early?
Usually — check the contract for a prepayment penalty. Extra payments go to principal and cut both the term and the interest: worked out month by month, an extra $100 a month on the example loan pays it off nine months early and saves about $1,060. Make sure extra amounts are applied to principal rather than counted as an early next payment.
What is negative equity and how do I avoid it?
Negative equity — being "underwater" or "upside down" — means you owe more than the car is worth. It comes from small down payments, long terms and depreciation, and it is a problem when the car is totaled (insurance pays its value, not your loan) or when you want to trade it in. A larger down payment and a shorter term reduce it; gap coverage protects against it.