Car Payment Calculator

Last updated: 2026-10-01

This car payment calculator estimates your monthly auto loan payment the way the deal actually works: vehicle price minus your down payment and trade-in, plus sales tax and fees. Use it as an auto loan calculator before you visit the dealer, so you walk in knowing the real number — not just the sticker price.

What this car payment calculator does

A car payment calculator turns the price on the windshield into the check you write every month. Type in the vehicle price and this tool folds in your down payment, trade-in value, sales tax, and fees, then computes the monthly payment for your APR and term. It works as a general car loan calculator too — new or used, dealer or private sale — because the math underneath is the same fixed-rate amortization behind every auto loan.

The result panel leads with the monthly payment, then shows the amount financed, the sales tax, total interest, total loan cost, and total paid including your down payment and trade-in. That last line matters: it answers what the car actually costs you, start to finish.

How to use it

Everything recalculates live as you type. Here's what each input means.

Vehicle price ($): the negotiated selling price of the car, before anything is subtracted or added. Default $35,000.
Down payment ($): cash you're putting in on day one. It comes straight off the amount you borrow.
Trade-in value ($): what the dealer gives you for your old car. It reduces the amount financed and the sales tax, because tax is figured on price minus trade-in.
Sales tax rate (%): your state and local rate combined. The tool applies it to (price − trade-in), which is the common US treatment — a few states handle trade-ins differently.
Fees ($): title, registration, and dealer fees. The default is $500; doc fees alone can run several hundred dollars depending on the state.
APR (%): the annual rate on the loan. This is the single biggest lever on your payment after the price itself.
Loan term: 36, 48, 60, 72, or 84 months. Longer terms shrink the payment and grow the total interest.

Worked examples

Example 1 — the defaults. A $35,000 car, $5,000 down, no trade-in, 6% sales tax, $500 in fees, 7% APR for 60 months. Sales tax comes to $2,100, so the amount financed is $32,600. The monthly payment is $645.52, total interest $6,131.14, and the total loan cost $38,731.14. The sticker said $35,000; the loan costs almost $39,000.

Example 2 — trade-in and term choice. A $28,000 car, $3,000 down, an $8,000 trade-in, 6.5% tax, $400 in fees, 6.9% APR. Tax is figured on $20,000 (price minus trade-in), so it's $1,300 instead of the $1,820 it would be without the trade-in — a $520 tax saving. Amount financed: $18,700. At 60 months the payment is $369.40 with $3,464.05 in interest; stretch to 72 months and the payment drops to $317.92 but interest climbs to $4,190.18 — $726.14 extra for a $51.48 lower payment.

Both examples were computed with the same formulas this page uses, so you can reproduce every figure by entering the same inputs above.

How the math works

The tool builds the loan in two steps. First, the amount financed:

financed = price − down payment − trade-in + sales tax + fees

where sales tax = (price − trade-in) × tax rate. Then it runs the standard loan amortization formula on that financed amount at your APR over the term — the same math behind our loan calculator. Each monthly payment covers that month's interest first, then chips away at the balance. Full formulas and assumptions live on our methodology page.

One consequence worth seeing: because interest is charged on the remaining balance, which is largest at the start, a longer term doesn't just add more payments — it keeps the balance (and the interest on it) higher for longer. That's why the 72-month version of Example 2 costs $726 more in interest, not just twelve extra payments' worth of principal.

Common mistakes and tips

Shopping the sticker price, not the out-the-door price. Tax and fees added $2,600 to Example 1 before a dollar of interest. Always compare cars by the financed amount, not the windshield number.
Putting too little down. The common guideline is 20% down on a new car. It shrinks the loan, often unlocks a better APR tier, and keeps you from owing more than the car is worth as it depreciates.
Ignoring the trade-in tax credit. In most states, trading in cuts your taxable amount. Example 2's $8,000 trade-in saved $520 in sales tax on top of reducing the loan. A few states don't allow it, so check yours.
Stretching to 72 or 84 months for the payment. The payment feels manageable, but you pay far more interest and stay underwater longer — owing more than the car is worth for years. If the 60-month payment doesn't fit your budget, the car is too expensive, not the term too short.
Accepting dealer fees without question. Doc fees range from under $100 to nearly $1,000 depending on the state. Ask what's negotiable and what's required by law.
Financing at the dealer without a competing offer. Get pre-approved by your bank or credit union first. A competing APR in your pocket is the best negotiating tool you have, and you can still take the dealer's financing if it beats it.

Frequently asked questions

How much car can I afford?

A common guideline is to keep your total car costs under 15% of your monthly take-home pay — that's the same 15% figure our affordability calculator uses. Run your income through it to see the payment your budget actually supports, then shop cars that fit the payment, not the other way around.

What is a good down payment on a car?

20% is the widely cited target for a new car, less for used. A bigger down payment shrinks the amount financed, can move you into a better APR tier, and protects you from going underwater — owing more than the car is worth — as it depreciates.

How does a trade-in affect my auto loan?

Two ways: it reduces the amount you finance, and in most states it reduces your sales tax because tax is figured on the price minus the trade-in. An $8,000 trade-in can save around $520 in sales tax alone at a 6.5% rate. A few states don't allow the credit, so confirm your state's rule.

What fees are normal when buying a car?

Expect title and registration fees set by your state, plus a dealer documentation fee. Doc fees vary enormously by state — under $100 in some, several hundred in others — so ask which fees are legally required and which are negotiable.

Is a 72- or 84-month car loan a bad idea?

It lowers the monthly payment but raises total interest substantially and keeps you owing more than the car is worth for years. Stretching from 60 to 72 months on an $18,700 loan costs an extra $726 in interest. If the 60-month payment doesn't fit, consider a cheaper car rather than a longer loan.

Should I get pre-approved before going to the dealer?

Yes. A pre-approval from your bank or credit union gives you a baseline APR to beat, which keeps the dealer's financing offer honest. Enter that APR in this calculator so you know your payment before you negotiate the price.