Monthly payment, total interest and total cost for any fixed-rate loan.
A fixed-rate loan is repaid in equal monthly instalments using the same amortisation formula as a mortgage: each payment covers the month's interest first, with the rest reducing the balance. Early on, most of the payment is interest; as the balance falls, more goes to principal. Two levers matter most. A higher rate raises both the monthly payment and the total interest. A longer term lowers the monthly payment but increases the total interest paid, sometimes dramatically — stretching a car loan from four years to seven cuts the payment but can add thousands in interest. This works for car, personal and student loans; for a home loan with taxes and insurance, use the mortgage calculator.