How Car Loan Calculators Compute Monthly Payments, With a Worked Example

A car loan calculator relies on a standard amortization formula that takes the borrowed principal, the monthly interest rate, and the number of payments to produce a fixed monthly cost. The article presents this formula along with a JavaScript implementation and notes the special handling needed for a 0% interest rate. Using a $25,000 loan at 6.35% APR, it shows that a 60-month term yields about $487 per month with roughly $4,244 in total interest, while a 72-month term lowers the payment but adds about $885 in total cost. It also highlights that each extra $1,000 down payment trims about $19 from a 60-month payment and that a one-point rate difference matters substantially over the life of the loan. The piece suggests working backward from an affordable monthly payment to determine a suitable car price.