How to calculate car loan interest payments There are several ways to calculate your monthly auto loan interest payment. You can use an online loan payment calculator or work directly with a lender.

Doing the math and crunching the numbers when it comes to figuring out your loan's interest can be complicated. Here's how to calculate interest on a loan.

Formula for calculating amortized interest Here’s how to calculate the interest on an amortized loan: Divide your interest rate by the number of payments you’ll make that year.