Auto Loan Calculator
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What Your Result Means
- Loan Amount: The total financed — your vehicle's price minus down payment and trade-in, plus sales tax on the taxable amount. This is the principal the lender is lending you.
- Monthly Payment: The fixed amount you pay each month for the loan term, covering principal and interest.
- Total Interest Paid: The cumulative cost of financing. Longer terms and higher rates increase this significantly — a 72-month loan can cost thousands more than a 48-month loan on the same car.
- Total Cost: All monthly payments combined — the full amount leaving your pocket over the life of the loan (not including down payment or trade-in).
How This Calculator Works
You enter the vehicle price, down payment, trade-in value, sales tax rate, interest rate, and loan term. The tool subtracts the down payment and trade-in from the price, applies sales tax to the taxable balance, then runs the standard amortization formula with monthly compounding. It assumes a fixed rate, no dealer add-ons, no GAP insurance, and no prepayment penalties.
Quick Questions
What loan term should I choose?
Shorter terms (36–48 months) have higher monthly payments but save significantly on total interest. Many financial planners suggest keeping auto loans at 60 months or less to avoid being "upside down" — owing more than the car is worth. Only stretch to 72–84 months if the rate is very low.
Is sales tax applied to the trade-in?
In most U.S. states, you only pay sales tax on the difference between the new car price and trade-in value, which this calculator models. However, a few states tax the full purchase price regardless. Check your state's rules.
What interest rate can I expect?
Rates depend on your credit score, the loan term, and whether the car is new or used. Excellent credit (750+) typically qualifies for the lowest advertised rates. Dealership financing may be convenient but isn't always the cheapest — get pre-approved through your bank or credit union first for comparison.
Should I put more down or invest the cash?
A larger down payment reduces the loan amount, lowers monthly payments, and cuts total interest. If your auto loan rate is low (under 4–5%), some prefer to invest the difference. The right call depends on your rate, risk tolerance, and cash reserves.
Does this include insurance and maintenance?
No. This calculator covers the loan only. Budget separately for insurance (typically $1,200–$2,400/year), fuel, maintenance, and registration. The true cost of car ownership is significantly higher than the monthly payment alone.
Sources
- CFPB — Auto Loans (auto financing basics and consumer rights)
- FTC — Buying a New Car (dealer financing disclosures and consumer tips)
- Federal Reserve G.19 — Consumer Credit (benchmark auto loan rate data)
Method & review
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.