How does an auto loan calculator work?
An auto loan calculator estimates a fixed monthly car payment using the amount financed, annual percentage rate (APR) and number of monthly payments. The amount financed can include vehicle price, taxes and fees, minus down payment, rebates and net trade-in equity.
Auto loan formula
For a fixed-rate loan, monthly payment is calculated as:
Payment = P × r × (1 + r)n ÷ [(1 + r)n − 1]- P = amount financed
- r = monthly interest rate (APR ÷ 12 ÷ 100)
- n = number of monthly payments
At 0% APR, the payment is amount financed divided by the number of months.
How to use this car payment calculator
- Enter the vehicle price and any cash rebate.
- Enter your down payment and trade-in value, plus any remaining loan payoff on the trade-in.
- Enter sales tax, fees, APR and the loan term in months.
- Choose the sales-tax method that matches your local rules or dealer quote.
- Select Calculate Auto Loan to review the monthly payment, total interest and repayment schedule.
Understanding trade-in equity
Net trade-in equity equals trade-in value minus the remaining loan payoff. Positive equity can reduce the amount you need to finance. If the payoff is higher than the trade-in value, you have negative equity, which increases the amount financed when rolled into the new loan.
What affects your car payment?
- Amount financed: A higher financed amount generally increases the payment.
- APR: A higher interest rate generally increases monthly payment and total interest.
- Loan term: Longer terms generally reduce the payment but can increase total interest.
- Taxes and fees: Adding them to the loan increases the amount financed.
- Trade-in equity: Positive equity may reduce the amount financed; negative equity may increase it.
Frequently asked questions
Does the calculator include down payment and trade-in?
Yes. It subtracts the down payment, rebate and net trade-in equity when calculating the estimated amount financed.
What if I still owe money on my trade-in?
Enter the remaining payoff. If it exceeds the trade-in value, the negative equity increases the amount financed in this estimate.
Can I calculate a 0% APR auto loan?
Yes. At 0% APR, the calculator divides the amount financed evenly across the selected number of monthly payments.
Does the calculator know my local sales tax rules?
No. Choose the full-price or trade-in-adjusted tax method and enter the rate that applies to your purchase. Local rules can differ, so confirm with your dealer or tax authority.
Are insurance and fuel included?
No. Insurance, fuel, maintenance and other ownership expenses are excluded. Add relevant fees to the fees field only if they will be financed as part of this loan.
Will my lender's payment be exactly the same?
Not necessarily. This is a fixed-rate estimate. Your lender may use different rounding, fees, tax treatment or payment timing. Confirm the official payment schedule before signing.
Financial disclaimer: This calculator is for general educational estimates only. It is not financial advice, a lending offer, or an approval. Actual contract terms and applicable taxes and fees determine your final cost.