If a lender uses the simple interest method, it’s easy to calculate loan interest. You will need your principal loan amount, ...

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.

If you aren't sure of the original balance, subtract the interest paid from the current balance. The interest paid: the difference between your original account balance and its current balance.