Auto Loan Calculator
The Auto Loan Calculator estimates your monthly car payment by factoring in the vehicle price, sales tax, trade-in value, down payment, interest rate, and loan term. The calculator applies sales tax to the full vehicle price before subtracting your down payment and trade-in credit — which matches how most states compute the taxable amount, though a handful of states instead tax the price minus trade-in credit only, so your dealer's actual tax line may come in lower than this estimate. If your down payment and trade-in together exceed the taxed vehicle price, the amount financed is floored at $0, showing a $0 monthly payment rather than a negative loan balance. The underlying formula is the same fixed-rate amortization math used for mortgages, so the standard tradeoff applies: stretching the term lowers the monthly payment but increases the total interest paid over the life of the loan.
How This Tool Works
Enter the vehicle price, any down payment or trade-in value, your local sales tax rate, interest rate, and loan term to calculate your monthly payment.
Formula & Method
Amount financed = vehicle price + sales tax − down payment − trade-in value. Monthly payment uses the standard amortization formula applied to that financed amount.
Example Calculation
A $28,000 car with a $2,000 down payment, a $5,000 trade-in, 6% sales tax, financed at 5.5% APR over 48 months. Sales tax: $28,000 × 6% = $1,680. Amount financed: $28,000 + $1,680 − $2,000 − $5,000 = $22,680. Monthly interest rate: 5.5% ÷ 12 ≈ 0.4583%. Plugging those into the amortization formula gives a monthly payment of about $527.46. Over 48 months that's $527.46 × 48 ≈ $25,317.93 total paid, meaning about $25,317.93 − $22,680 = $2,637.93 goes to interest.
Frequently Asked Questions
Does this include sales tax?+
Yes, sales tax is calculated on the vehicle price and added to the amount financed — though some states tax differently after trade-in credit, so check your local rules.
Should I use my trade-in value or payoff amount?+
Use the amount the dealer is crediting you for your trade-in. If you still owe money on it, that payoff amount typically gets rolled into your new loan separately.
What loan term should I choose?+
Shorter terms mean higher monthly payments but less total interest. Longer terms lower your payment but usually cost more in total interest over the life of the loan.
How do I account for negative equity I'm rolling over from a previous car loan?+
There's no dedicated field for negative equity. To approximate its effect, reduce the trade-in value you enter (or your down payment) by the amount you still owe — both fields are subtracted directly from the amount financed without any tax applied, so lowering either one raises your amount financed by the same dollar amount as an unpaid balance would.
What happens if my down payment and trade-in together cover more than the car's price and tax?+
The amount financed is floored at $0 rather than going negative, so the calculator shows a $0 monthly payment — meaning you're covering the full purchase in cash and don't need financing for the difference.
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<a href="https://everyfix.net/tools/auto-loan-calculator/">Auto Loan Calculator</a> by <a href="https://everyfix.net">EveryFix</a>Related Tools
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