Auto Loan Calculator
Turn a sticker price into the real monthly payment. Enter the price, your trade-in and down payment, your state sales tax, and the APR and term, and this calculator returns the monthly payment, the total interest, and a full payment-by-payment schedule.
It uses the standard amortization formula lenders use, and applies sales tax after the trade-in credit — the rule in most states — so the amount financed matches what you would actually sign for.
Calculator
Monthly payment
$960.62
$47,940 financed at 7.5% for 60 mo
Total interest
$9,697
Sales tax
$2,940
Total of payments
$57,637
| Year | Principal | Interest | Balance |
|---|---|---|---|
| Year 1 | $8,210 | $3,317 | $39,730 |
| Year 2 | $8,848 | $2,680 | $30,882 |
| Year 3 | $9,535 | $1,993 | $21,347 |
| Year 4 | $10,275 | $1,253 | $11,072 |
| Year 5 | $11,072 | $455 | $0 |
Calculation Formulas
Sales tax is applied after the trade-in credit (the rule in most states), then the down payment is subtracted.
Example:
$32,000 car, $2,000 trade-in, 7% tax, $3,000 down → tax = 7% × $30,000 = $2,100 → financed = $30,000 + $2,100 − $3,000 = $29,100.
P is the amount financed, r is the monthly rate (APR ÷ 12), and n is the term in months. This is the standard fixed-rate loan formula U.S. lenders use.
Key Figures
| Figure | Value | Description |
|---|---|---|
| Common terms | 48 / 60 / 72 months | The most widely offered new-car loan lengths. |
| Trade-in tax credit | Most states | Sales tax is charged on price minus trade-in in most states; a few tax the full price. |
Note: Results are estimates for planning purposes. Rates, fees, taxes, and insurance vary by lender and location — confirm exact figures with a licensed professional before making financial decisions.
Standards & Sources
Last verified: November 2026
- Truth in Lending Act (TILA) — APR disclosure
Lenders must disclose the APR, which includes certain finance charges — the number to compare offers on.
- State motor-vehicle sales tax rules
Whether a trade-in reduces taxable price varies by state; this calculator applies the common trade-in credit. Confirm your state’s rule for an exact figure.
How to use this calculator
- Enter the vehicle price and any trade-in value and cash down payment.
- Enter your state sales-tax rate so the amount financed is accurate.
- Enter the APR your lender or credit union quoted and choose the loan term.
- Read your monthly payment, total interest, and the amortization schedule.
Frequently Asked Questions
How is my car payment calculated?
From the amount financed, your APR and the loan term, using the standard amortization formula. The amount financed is the price minus trade-in, plus sales tax, minus your down payment.
Does a trade-in reduce my sales tax?
In most states, yes — sales tax is charged on the price after the trade-in credit. A few states tax the full price. The calculator uses the common trade-in-credit rule.
Is a longer loan term a good idea?
A longer term lowers the monthly payment but increases the total interest, and keeps you underwater — owing more than the car is worth — for longer. Compare the total interest, not just the payment.
What APR should I expect on a car loan?
It depends on your credit, the lender and whether the car is new or used. Always compare on APR, which includes finance charges, and get a credit-union quote before accepting dealer financing.
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