Updates automatically as you type.
Calculated in your browser; your inputs are not sent to us. Privacy
Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
This tool runs in your browser. Your calculator inputs and results are never transmitted to us or to ad/affiliate partners. Ads and sponsored links may set third-party cookies to serve and measure them, but they never receive your calculation values. If you explicitly save a scenario, its permitted fields stay in local browser storage until you clear them. See our Privacy Policy.
Use this result
Share the current inputs or ask ChatGPT to explain the calculation in context.
More options
What does this calculator estimate?
Auto loan calculator: estimate monthly payment, total interest, and payoff cost from price, down payment, rate, and term. Free, runs locally in your browser.
Choose a term by total interest, not monthly payment
On a $32,000 loan at 7% APR, a 60-month term costs $633 a month and $6,020 in interest. A 72-month term drops the payment to $546 but pushes interest to $7,320, a difference of about $1,300 for the privilege of stretching payments another year. An 84-month term, which many lenders now advertise, drops the payment to $478 but raises interest to $8,210, another $890 on top of that. The monthly number falling feels like saving money. It is the opposite: the total you repay grows every time you extend.
The honest way to pick a term is to decide what you can pay, then borrow to that term. If $633 is affordable, taking 72 months and paying the difference to the principal each month gives you a 60-month payoff with the flexibility to stop, which is worth something if your income is unstable. What is not defensible is signing an 84-month note because the payment looks small: by year five you are paying $478 a month on a nine-year-old car worth perhaps $8,000, and you still owe more than a year of payments. Enter your real rate, not an advertised teaser, and compare the running interest total across terms rather than the monthly line.
Why dealer 0% APR offers rarely beat a cash rebate
Manufacturers often run a promotion with two mutually exclusive offers: 0% APR financing for 60 months, or a $3,000 cash rebate with regular financing. The arithmetic favors one of them almost every time, and not always the one that sounds better. Take a $34,000 vehicle. Financing $34,000 at 0% costs zero interest. Financing $31,000 (price minus the rebate) through a credit union at 6.5% APR costs about $5,390 over 60 months in interest, so 0% wins by about $2,390. Now suppose the rebate is $5,000: financing $29,000 at 6.5% costs $4,570 in interest, and the rebate option now beats 0% financing by roughly $430.
Neither number is possible to know in advance, which is why this calculator matters when you are mid-deal. Enter the loan amount without the rebate at the promotional rate, then enter the reduced loan amount with the rate you have actually been preapproved for, and read the total interest from both. One caution: promotional rates are usually restricted to well-qualified buyers, sometimes requiring a 750 or higher score, and the fine print often excludes some trim levels. If you get no promotional rate, the calculator is telling you that the rebate walk-away is a fact, a rebate you qualify for is usually worth more than a rate cut you do not.
Negative equity rolled into the new loan: the quiet four-figure cost
About one in five trade-ins in recent years has carried negative equity, meaning the owner owed more than the car brought at trade. The next deal rolls the gap into the new loan, which is small on paper and large over time. A real example: you owe $21,000 on a car worth $17,500, so $4,000 of negative equity gets added to a $30,000 loan on your next car; the financed amount becomes $34,000 plus tax. At 7% over 72 months, that $4,000 of dead weight costs about $530 a month's worth of extra payment and roughly $880 in extra interest over the term.
Worse, leveling the next loan's negative equity creates a stack effect: at year four of that new loan, the car has depreciated normally but your balance is $6,000 to $8,000 deeper than a clean loan would have been, so the next trade rolls an even bigger gap. This calculator has no field for rolled-in negative equity, so you must add it to the vehicle price manually. If you are trading and the dealer states your payoff and trade value, the gap goes in as an upward adjustment to the price, and compare that deal against one where you sell the old car yourself. Private sale almost always nets more than trade-in, and closing that gap keeps your next loan whole.
Refinancing an auto loan: the months where it pays and the months it does not
Car loan refinancing is the cheapest credit decision you will make in any given year, partly because the payoff math is identical to mortgage math on a smaller denominator. Suppose 18 months ago you financed $28,000 for 60 months at 9.9%, and your score has since pushed 760. A 5.9% refinance on the remaining $22,700 at the same 42 months remaining cuts the payment by about $64 and saves about $2,690 over the remaining term. That qualifies. On the other end of the scale, a lender that charges a $350 origination fee, a $150 title fee, and a 9% rate on a $22,000 balance with 30 months left is probably not worth the paperwork; the break-even there depends on whether the payment moves at all.
There are two conditions that make refinancing unattractive. First, if you have already paid more than half the term, most of the interest is behind you, and a lower rate cuts less than the front-loaded amortization already collected. Second, if stretching the term is what makes the refinance affordable, the payment reduction is an illusion that hides a longer repayment. Check both before acting: enter the remaining balance and remaining months at your current rate, then again at the offered rate for the same term. If the term changes, the comparison is invalid. A refinance that lowers your rate and shortens or holds the term is the only kind worth shopping.
How this calculator works
Assumptions to verify
- Sales tax is applied to the vehicle price less the trade-in credit. Some jurisdictions tax the full price before the trade is deducted, so enter the tax amount yourself if your state works that way.
- The APR you enter is treated as fixed for the entire term. A balloon payment, a variable rate, or a buy-rate the dealer marked up will not match this result.
- Title, registration and dealer fees are entered as one flat amount paid at signing rather than financed separately.
- Insurance, maintenance, fuel and fuel tax are excluded. Only principal and interest are modelled.
Cite this tool
BoringToolsKit. “Auto Loan Calculator.” boringtoolskit.com/auto-loan-calculator/ (reviewed August 2026). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Any future sponsored recommendation or advertisement will be clearly labeled and kept separate from the calculation.
$25k auto loan, 6%, 60 months
What this means for your numbers: In the worked example, interest is 13.8% of the amount financed ($4,000 of $29,000). Every $1,000 of extra down payment at 6% saves about $160 of interest over 60 months.
Illustrative breakdown using the worked example above. The calculator computes your own numbers with the same formula.