# How to Calculate Mortgage Interest

The interest on a loan is the amount of money you pay to a lender in addition to your principal (the amount that you borrowed). Interest is typically provided as a percentage, such that the interest rate is a given fraction of the principal. A mortgage loan is a type of loan used to finance the purchase of a property. You can calculate interest paid on a mortgage loan using the interest rate, principal value (property price), and the terms of the loan (the duration and number of payments). This can be done in a number of ways, depending on what information you have and your personal preference.

### Method 1 Calculating Interest Quickly and Easily

1. 1
Use an online mortgage loan calculator. There is a variety of online calculators that will find your monthly payment and interest paid with the simple input of a few pieces of key information. Try searching for "mortgage loan calculator" using your preferred search engine. Usually, you'll have to input details of your loan, like the number of years, annual interest rate, and value of your principal. Then, simply hit "calculate" and the provided readout should tell you anything else you need to know.[1]
• This can also be a useful way to compare mortgage plans. For example, you may be deciding between a 15-year loan at 6 percent or a 30-year loan at 4 percent. The calculator will help you easily see that, despite the higher interest rate, the 15-year loan is a cheaper option.
2. 2
Calculate total interest using loan payments. Similar to the quick method above, this one will allow you to calculate the total interest you will pay on your loans, assuming you already know your monthly payment. However, here you will be multiplying your monthly payment by the number of payments to arrive at a total amount paid over the life of the loan.
• Start by finding your monthly payments either on a recent bill or on your loan agreement.