Auto Loan Calculator

Estimate your monthly car payment, total interest, and the true cost of the vehicle after tax, down payment, and trade-in.

How the auto loan calculator works

Before any payment math, the calculator figures out how much you’re actually financing. Sales tax is applied to the price minus your trade-in — the rule in most states — and rolled into the loan along with the price itself. Your down payment and trade-in credit then come off, leaving the amount financed.

The monthly payment uses the standard amortization formula: the rate is converted to a monthly rate, and the payment is set so principal plus interest retires the balance exactly at the end of the term. Early payments are mostly interest; later ones are mostly principal, which the year-by-year chart makes visible.

The monthly payment is only part of the story. The calculator also reports total interest over the life of the loan and the true all-in cost of the car — your down payment and trade-in plus every monthly payment — which is the number to compare when choosing between terms or deciding how much car to buy.

How to use this calculator

Enter the negotiated vehicle price — before tax, title, and dealer fees.
Enter your down payment and any trade-in credit.
Enter your state’s sales tax rate.
Enter the APR you’ve been quoted and choose a loan term in months.
Press Calculate to see the monthly payment, total interest, payoff date, and true cost of the car.

Key terms

Amount financed: What you actually borrow: the vehicle price minus your trade-in, plus sales tax, minus your down payment.
APR: Annual percentage rate — the yearly cost of the loan including interest and lender fees. It’s the number to compare across lenders.
Amortization: The schedule that splits each level payment between interest and principal until the loan reaches zero at the end of the term.

Tips

Get pre-approved by a bank or credit union before visiting the dealer — a competing rate in hand is the strongest negotiating tool there is.
Shorter terms cost less overall: a 48-month loan at the same rate saves hundreds or thousands in interest versus 72 months, and keeps you from owing more than the car is worth.
Put at least 10–20% down. New cars depreciate fastest in year one, and a small down payment leaves you underwater on the loan almost immediately.

Frequently asked questions

How much car can I afford?

A common guideline is to keep the payment at or below 10–15% of your take-home pay, and total transportation costs — payment, insurance, fuel, maintenance — below 20%. Run the payment here, then check the full picture with our 50/30/20 budget calculator.

Is sales tax really added to the loan?

Usually, yes. Most buyers roll sales tax into the financing rather than paying it upfront, so this calculator adds it to the amount financed. In most states the tax applies to the price after subtracting your trade-in, which is how the tax figure here is computed — a few states tax the full price, so check your state’s rule.

Why is a longer loan term risky?

Two reasons: you pay far more total interest, and the car depreciates faster than the balance falls — leaving you owing more than the car is worth for much of the loan. If you need a 72- or 84-month term to afford the payment, the car is probably too expensive.

Does this calculator include insurance, title, and dealer fees?

It includes sales tax but not registration, title, documentation fees, or insurance — those vary too much by state and insurer. Add them to the vehicle price if you plan to finance them, or budget to pay them upfront.

How can I pay less interest on a car loan?

Four levers: negotiate a lower price, improve your credit score before applying (rate tiers move sharply with score), choose a shorter term, or make a bigger down payment. Once you have the loan, extra principal payments shorten it — our loan payoff calculator shows exactly how much they save.

Planning further? Try the loan payoff calculator or the debt-to-income ratio calculator.

Loan Payoff Calculator

Find out when your loan will be paid off and how much interest extra monthly payments can save.

Debt-to-Income Ratio Calculator

Calculate your front-end and back-end DTI ratios to see how lenders view your debt load.