Auto Loan Calculator

Estimate your monthly car payment, total interest and all-in cost — including sales tax, trade-in and down payment — with a full amortization schedule.

Vehicle Price

Down Payment

Trade-In Value

Sales Tax Rate (%)

APR (%)

Loan Term (months)

Frequently Asked Questions

Does it include sales tax and trade-in?

Yes. Sales tax is applied to the price less your trade-in, and both your trade-in and down payment reduce the amount you finance.

What APR should I use?

Enter the annual percentage rate (APR) your lender or dealer quoted you. It reflects your credit, the term, and current market rates.

Does it show total interest?

Yes. You get total interest and total cost, plus a full month-by-month amortization schedule and a balance chart.

Understanding the Auto Loan Calculator

The Auto Loan Calculator estimates your monthly car payment and the true cost of financing a vehicle. Enter the vehicle price, down payment, trade-in value, sales tax rate, APR, and loan term in months, and it instantly shows your monthly payment along with the financed loan amount, total interest, sales tax, and all-in cost. It correctly folds sales tax into the amount you borrow and subtracts both your down payment and trade-in. A month-by-month amortization schedule and a balance chart reveal exactly how each payment splits between principal and interest. Everything runs in your browser and respects the site currency switcher.

How it works

First the tool calculates sales tax on the price minus your trade-in (most states tax the difference). It then builds your financed loan amount: vehicle price plus sales tax, minus down payment and trade-in. The monthly payment uses the standard amortization formula at a monthly rate of APR divided by 12. Each month, interest is charged on the outstanding balance and the rest of your payment reduces principal, which is why early payments are interest-heavy. The calculator totals every payment to derive total interest, then adds price, tax, and interest for the all-in cost. The schedule and chart visualize the falling balance and rising principal paid over the full term.

salesTax = max(0, price − tradeIn) × taxRate% loanAmount = price + salesTax − downPayment − tradeIn Monthly rate r = APR ÷ 12 ÷ 100 Payment M = L × r × (1+r)^n ÷ ((1+r)^n − 1), where L = loanAmount and n = term in months (if r = 0, M = L ÷ n) Total interest = M × n − L Total cost = price + salesTax + total interest

Worked example

Suppose you buy a $35,000 car with $5,000 down, no trade-in, a 7% sales tax, a 6.5% APR, and a 60-month term. Sales tax is $35,000 × 7% = $2,450, so you finance $35,000 + $2,450 − $5,000 = $32,450. At 6.5% APR over 60 months, the monthly payment is about $635. Over the full term you pay roughly $5,640 in interest, for an all-in cost of about $43,090 including the price, tax, and interest.

Tips & common mistakes

Tax is usually applied to price minus trade-in, so a larger trade-in lowers both your loan and your sales tax.
A bigger down payment cuts the financed amount and the interest you pay over the life of the loan.
Shorter terms mean higher monthly payments but far less total interest — compare 48 vs 60 vs 72 months.
Use the APR your lender quotes, not the base interest rate, since APR includes certain financing fees.
Check the sales tax rules for your state — some tax the full price rather than the price after trade-in.
Watch the amortization schedule: in the early months most of your payment goes to interest, not principal.

Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.