Last reviewed September 2026
Sensible default. Modify inputs to match your situation.
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Auto loan calculator. Vehicle price, down payment, trade-in, and sales tax rolled into one real monthly payment, with total interest, payoff date, and the full amortization schedule.
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An auto loan calculator that only asks for price, rate, and term is missing two things that change your real payment a lot: your trade-in and your sales tax. Most states tax the vehicle price minus whatever your trade-in is worth, not the sticker price, and that tax is usually rolled into the loan rather than paid separately at signing. This calculator includes both, so the payment you see here is closer to the one your finance office will actually show you.
Say a vehicle costs $32,000 and you trade in a car worth $5,000 with no cash down. In a state with a trade-in tax credit, sales tax is charged on $27,000 (the price minus the trade-in), not the full $32,000. At a 7% rate that is $1,890 in tax instead of $2,240, an $350 difference before a single payment is even calculated. The trade-in value is then also subtracted from the price to set the loan amount itself, so it lowers your payment twice over: once against principal, and again against the tax base. Not every state offers this credit; a handful tax the full sale price regardless of a trade-in, so check your own state's rule if the exact dollar figure matters to you. If you're weighing a straight installment loan instead of vehicle financing, the Loan Calculator runs the same amortization math without the trade-in and tax fields.
Financing the tax into the loan is the common default at most dealerships, and it's what this calculator assumes. Some buyers cover tax, title, and registration fees out of pocket instead, in which case the loan amount itself would only reflect the price minus trade-in minus down payment, with no tax added on top; lower the down payment field here if you want to model paying tax separately with cash. Curious whether financing versus paying cash is worth it at all? The Compound Interest Calculator shows what that same down payment could grow into if invested instead.
Stretching a loan from 60 to 72 or 84 months lowers the monthly payment, which is real budget relief, but it does not lower the total cost. On the $31,240 financed above at 7.5% APR, 60 months runs $625.99/mo with $6,319.13 total interest. The same loan at 72 months drops to $540.14/mo, but total interest climbs to $7,650.30, $1,331.17 more, because interest keeps accruing on a slower-shrinking balance for a full year longer. There's a second cost that isn't in the interest number at all: for a long stretch of a longer loan, you can owe more than the vehicle is worth as it depreciates, which is a real risk if the car is totaled or you need to sell before payoff. If a high-interest card is also in the picture, run it through the Credit Card Payoff Calculator to see which balance actually deserves the spare dollar first.
It assumes a single fixed APR for the full term, not a promotional teaser rate that adjusts, and it does not model dealer add-ons like extended warranties, gap insurance, or gap coverage bundled into the loan, title and registration fees beyond the sales tax field, or a co-signer's effect on your approved rate. Sales tax rates and trade-in credit rules are entered by you, not looked up automatically, since they vary by state and sometimes by county. For a general installment loan without vehicle-specific fields, see the Loan Calculator.
Sales tax is calculated on the vehicle price minus the trade-in value, then added to the amount financed along with the price minus trade-in minus down payment: Amount financed = (Price − Trade-in − Down payment) + (Price − Trade-in) × Tax rate. The monthly payment uses the standard fixed-rate amortization formula: M = P[r(1+r)^n] / [(1+r)^n − 1], where P is the amount financed, r is the monthly interest rate (APR ÷ 12), and n is the loan term in months. Total interest is the sum of all payments minus the amount financed. The payoff date adds the loan term in months to today's date. Dollar figures round to the nearest whole dollar for display; the full-precision value is carried through every step before that final rounding. This same amortization formula is the starting point for the Loan Calculator and the Mortgage Payment Calculator.
Yes. Enter your state or local sales tax rate and the calculator applies it to the vehicle price minus your trade-in value, the way most states with a trade-in tax credit calculate it, then finances that tax into the loan along with the rest of the balance.
Your trade-in value is subtracted from the vehicle price before the loan amount is set, and in most states it also lowers the taxable amount, so it reduces your payment twice: once on the principal and again on the sales tax.
This calculator finances sales tax into the loan balance along with the rest of the amount owed, which is the common default at most dealerships. Some buyers choose to pay tax, title, and registration fees out of pocket at signing instead; if that's your plan, lower the down payment field to reflect a smaller cash outlay against principal only.
60- and 72-month terms are the most common for new vehicles, with some lenders offering up to 84 months. Rates vary widely by credit tier and whether the vehicle is new or used; check your own pre-approval or a current lender rate sheet rather than relying on this calculator's default APR.
A longer term spreads the same principal over more payments, so each payment is smaller, but interest keeps accruing on a slower-shrinking balance for more months. The lower monthly payment is real, but it comes from paying more total interest over the life of the loan, not from a cheaper loan.
On this calculator's $31,240 financed default at 7.5% APR, 60 months runs $625.99/mo with $6,319.13 total interest. Stretching the same loan to 84 months drops the payment to $479.17/mo but raises total interest to $9,010.09, about $2,690.96 more, and for a long stretch of the loan you would owe more than a depreciating vehicle is worth. A lower payment from a longer term is real relief if the budget is tight, but it is not free.
Disclaimer. This calculator is designed to estimate your monthly auto loan payment based on the inputs you provide. It is not financial advice or a loan pre-approval, and actual loan terms are not guaranteed. Actual payment amounts may vary based on lender policies, your credit profile, state and local sales tax rules, and dealer fees. This calculator uses a fixed-rate amortization formula and does not model a promotional or variable rate. Consult your lender or dealership finance office before making any purchase decision.