FigureNook

Auto Loan Calculator

Enter the price of the car, your down payment, any trade-in, the sales tax and the interest rate. The calculator shows your monthly payment and what the whole loan will cost.

Sales tax, fees and any money you still owe on your old car are rolled in, so the loan amount matches what a dealer would actually finance.

Trade-in, tax and fees

Monthly payment$0.00
Loan amount$0.00
Total interest$0.00
Sales tax$0.00
Total cost of the car$0.00
Year by year
YearPrincipalInterestBalance at year end

Please note: Estimate only. This is not financial advice. Your real rate, taxes and fees will vary. Check the numbers on your loan offer.

How it works

The loan amount starts with the price of the car. Sales tax, dealer and title fees, and anything you still owe on a trade-in are added. Your down payment and the trade-in value are subtracted. What is left is what you borrow.

Sales tax rules differ by state. In many states, including Texas, you only pay tax on the price after the trade-in value is taken off. In others you pay tax on the full price. The calculator has a box for each case. Use your state’s rule, and add the local rate if your city or county charges one.

The monthly payment comes from the standard loan formula, spread over the number of months you choose. A longer loan means a lower payment, but you pay more interest in total, and you stay in debt longer than the car keeps its value.

tax = (price − trade-in) × tax rate    (or price × rate if your state taxes the full price)
loan = price + tax + fees + trade-in balance owed − down payment − trade-in value
payment = loan × rate ÷ (1 − (1 + rate)^−months)

Worked example: A $30,000 car, 6% for 60 months

With no down payment, no trade-in and no tax, the loan is $30,000. The payment is $579.98 a month, and you pay about $4,799 in interest over five years.

Now a more realistic case. A $32,000 car, $3,000 down, a $6,000 trade-in, 6.25% sales tax and $400 in fees, financed at 6.5% for 60 months. Tax is on $26,000 after the trade-in, which is $1,625. The loan is $25,025, the payment is $489.64, and the interest comes to about $4,354.

Frequently asked questions

Is sales tax charged on the trade-in?

It depends on your state. Many states only tax the price minus your trade-in. Check your state’s motor vehicle or revenue department. Use the checkbox that matches your state.

What if I owe more on my old car than it is worth?

Enter the trade-in value and the amount you still owe. The unpaid part is added to your new loan, which raises both the payment and the interest. This is called negative equity, and it is worth avoiding if you can.

What loan length should I pick?

Shorter loans cost less in total. Many buyers choose 48 to 60 months. Loans of 72 months or more have lower payments, but the car can lose value faster than you pay the loan down.

Does this include insurance and fuel?

No. Those are on top of the loan payment. Add them to your own budget before you decide what you can afford.

Should I use the dealer’s rate or my bank’s?

Compare. Get a pre-approval from your bank or credit union first, then see if the dealer can beat it. Try both rates in the calculator.

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Content last reviewed 2026-10-13.