Estimate your monthly car payment and total interest from the vehicle price, down payment, trade-in, sales tax, APR, and loan term.
Monthly payment
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Total interest
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Amount financed
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How It Works
First the amount you finance is computed: vehicle price minus down payment and trade-in value, plus sales tax applied to the taxed portion of the price (price minus trade-in, in most states).
The monthly payment uses the standard loan amortization formula: M = P × r(1+r)^n / ((1+r)^n − 1), where P is the financed amount, r is the monthly interest rate (APR divided by 12), and n is the loan term in months.
Total interest is the total of all payments minus the financed principal. The calculator assumes a fixed-rate loan with equal monthly payments.
Worked example: a $32,000 car with $4,000 down and a $5,000 trade-in at 7.5% tax and 5.9% APR for 60 months. Taxable amount = $27,000, sales tax = $2,025, financed amount = $25,025. Monthly rate = 0.004917, so payment = 25025 × 0.004917 × (1.004917)^60 / ((1.004917)^60 − 1) ≈ $483/mo. Total interest ≈ $483 × 60 − $25,025 = $3,955.
Frequently Asked Questions
Does sales tax apply to the full vehicle price?
In most U.S. states, sales tax applies to the price minus any trade-in allowance. The calculator uses price minus trade-in as the taxed amount, which is the most common rule.
Should I include fees in the vehicle price?
Yes. Add title, registration, and dealer fees into the vehicle price field if you want them financed, or pay them upfront and leave them out.
How does a larger down payment affect my payment?
A larger down payment reduces the amount you finance, which lowers both your monthly payment and the total interest you pay over the life of the loan.
Is a 60-month or 72-month loan better?
A shorter term means a higher monthly payment but far less total interest. Stretching from 60 to 72 months on the worked example drops the payment from $483 to about $414 but raises total interest from ~$3,955 to ~$4,830.
What APR is considered good for a car loan?
As of 2024, under 6% is competitive for buyers with strong credit. Rates above 10% are common for subprime credit. Your APR depends on your credit score, loan term, lender, and whether the car is new or used.
Should I finance or pay cash for a car?
If your cash could earn a higher after-tax return than the loan APR, financing can make sense. If the loan APR is higher than your investment return or you value being debt-free, paying cash saves the most overall.