Auto Loan Calculator
This calculator starts where the deal actually starts: the amount you finance after your down payment and trade-in come off the price. Dealers negotiate in monthly payments; smart buyers negotiate the amount financed and the term — the two numbers that decide what the car really costs.
Educational estimate only — not financial advice. Results depend entirely on the numbers and assumptions you enter; real-world returns, rates, taxes, and fees will differ.
What is an auto loan payment?
An auto loan is an installment loan secured by the vehicle: you borrow the difference between the purchase price and what you pay upfront (down payment plus any trade-in), then repay it in equal monthly payments over a set term — commonly 36 to 72 months, with some loans now stretching to 84. Because the car is collateral, rates are lower than unsecured personal loans, but the lender can repossess the vehicle if payments stop, and you must keep the car insured to the lender's standards.
The amount financed is the number that matters, and it is easy to lose sight of it at the dealership. The out-the-door price includes the vehicle price plus sales tax, title and registration, and dealer fees, minus rebates. Every add-on rolled into the loan — extended warranties, service contracts, protection packages — becomes part of the amount financed and accrues interest for years. A $2,000 add-on on a 60-month loan at 7.5% really costs about $2,400. This calculator covers the core loan; add taxes and fees to the price field if you want an out-the-door estimate.
Cars also depreciate — a new vehicle typically loses a significant share of its value in the first few years — while loan balances fall on the amortization schedule. If the balance falls slower than the value, you are 'upside down' or in negative equity: you owe more than the car is worth. Long terms and small down payments make this likely, which matters if the car is totaled or you need to sell, because the payout or sale price will not cover the loan.
How an auto loan payment is calculated
The calculator subtracts your down payment and trade-in from the vehicle price to get the amount financed, then applies the standard amortization formula: the monthly rate is the APR divided by 12, and the term is entered directly in months, which is how auto loans are quoted. It then simulates the balance month by month to produce the payoff chart and totals.
Two inputs deserve care. The rate should be the APR you actually qualify for — advertised rates go to the strongest credit profiles, and the rate in a signed offer is the only one that counts. And the price should ideally be the out-the-door figure including taxes and unavoidable fees, since those are financed too. If you are estimating early in the process, add roughly your local sales tax on the vehicle price to be realistic rather than pleasantly surprised at signing.
Notice the asymmetry the formula creates between price and payment. Extending a loan from 60 to 72 months on $28,000 at 7.5% drops the payment by about $77 a month, yet adds roughly $1,193 of interest and keeps you in debt a full extra year — often past the point where the car's value has fallen well below the balance. Sales conversations emphasize the small monthly difference; the calculator exists to show the total difference.
The down payment works in the opposite direction with no downside except the cash itself: every extra $1,000 down removes $1,000 from the amount financed and saves about $205 of interest on a 60-month, 7.5% loan, while also protecting you against negative equity from day one.
Worked example
A $35,000 vehicle with $5,000 down and a $2,000 trade-in leaves $28,000 financed at 7.5% APR for 60 months. The calculator is pre-loaded with these numbers.
| Vehicle price | $35,000.00 |
| Down payment + trade-in | −$7,000.00 |
| Amount financed | $28,000.00 |
| Monthly payment | $561.06 |
| Total interest | $5,663.75 |
| Total cost of the loan | $33,663.75 |
The payment is $561.06, and the financing adds $5,663.75 to the cost of the car — on top of the $7,000 you put in upfront. So the $35,000 car really costs about $7,000 + $33,663.75 = roughly $40,600 all-in before tax, insurance, fuel, and maintenance. That all-in framing is the one to compare against your budget, not the sticker price and not the monthly payment in isolation.
Now try the counterfactual in the calculator: same car, 48 months instead of 60. The payment rises to about $677, but total interest falls to roughly $4,500 — about $1,167 saved — and you own the car free and clear a full year sooner, while it is worth more. If the higher payment fits, the shorter term is one of the simplest money wins in car buying.
Avoiding negative equity (being upside down)
Negative equity happens when the loan balance exceeds the car's market value. It is most likely with long terms (72–84 months), small down payments, and new cars, which depreciate fastest early. It becomes a real problem in three situations: the car is totaled and the insurance payout is less than the balance (gap insurance exists for exactly this), you need to sell or trade early and must pay cash to close the loan, or you roll the shortfall into the next car loan, starting the next loan even deeper underwater — a cycle dealers call 'burying' the buyer and one that compounds quickly.
The defenses are boring and effective: put at least 20% down if you can, keep the term at 60 months or less, and buy a car you can keep for years. The balance chart above shows the loan side of the race; compare its pace against realistic depreciation — if the balance curve sits above likely values for long, restructure the deal before signing, not after.
Dealer financing vs. bank or credit union pre-approval
Walking into a dealership with a pre-approval from your bank or credit union changes the negotiation: you already have a rate, so the dealer's financing must beat it to earn the loan, and the conversation stays on the car's price instead of drifting into monthly-payment framing. Captive lenders (the manufacturer's finance arm) sometimes offer promotional rates well below market on specific models — those are worth taking when the rebate math favors the rate over a cash rebate, which you can check by running both scenarios here.
Whatever the source, judge offers on three numbers from this page: amount financed, APR, and term — and the resulting total interest. A lower payment achieved by extending the term is not a better deal; it is a longer one.
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Frequently asked questions
How much should I put down on a car?
A common target is 20% of the price on a new car (10% or more on used), plus paying taxes and fees in cash if you can. A larger down payment cuts the amount financed, reduces interest, lowers the payment, and protects you against owing more than the car is worth.
Is a 72- or 84-month auto loan a bad idea?
It lowers the payment but raises total interest substantially and makes negative equity likely, because the balance falls slowly while the car depreciates quickly. It can also mean still paying for a car that needs major repairs. Terms of 60 months or less are the safer default for most buyers.
What APR should I expect on an auto loan?
It depends mainly on your credit profile, the term, and whether the car is new or used; used-car rates are usually higher. Well-qualified buyers get rates several points below borrowers with weaker credit. Get pre-approved before shopping so you know your real number.
Does my trade-in reduce the amount I finance?
Yes — the trade-in value is subtracted from the price just like cash down, as shown in this calculator. In many states it also reduces the taxable price. Make sure the trade-in figure in the deal is the amount actually credited, not a number offset by a higher vehicle price.
Should I pay taxes and fees in cash or finance them?
Paying them in cash keeps them out of the loan so you do not pay interest on them for years. On a $35,000 car, financing 7% sales tax adds about $2,450 to the amount financed. If cash is tight, financing them is common — just include them in the price here to see the true payment.