Use the loan amount: car price + taxes + fees – down payment – trade-in value
Convert the annual interest rate to a monthly rate: APR ÷ 12 ÷ 100
Determine the loan term in months: years × 12
Apply the payment formula: Payment = [Loan Amount × Monthly Rate] ÷ [1 – (1 + Monthly Rate)^(-Months)]
If the interest rate is 0%, use: Payment = Loan Amount ÷ Months
Add insurance, fuel, maintenance, and registration separately if needed
Use an online auto loan calculator for a quick estimate