Determine the loan amount: car price plus taxes, fees, and optional add-ons, minus down payment and trade-in value
Find the interest rate and loan term in months
Convert the annual interest rate to a monthly rate by dividing by 12
Use the loan payment formula: Payment = P × [r(1 + r)^n] ÷ [(1 + r)^n – 1]
Let P = loan amount, r = monthly interest rate, and n = number of months
Use an online auto loan calculator if you do not want to calculate it manually
Add insurance, fuel, maintenance, and registration costs to estimate total monthly car cost