It’s easiest to create an amortization schedule using a calculator because it does the math for you. Here’s the information you’ll need to enter.

A starting loan amount. If you already have a mortgage, be sure to use the loan amount from when your mortgage started. If you’re buying a home and have a down payment, subtract that from the loan amount.

An interest rate. Use your current interest rate if you already have a mortgage. If you’re buying a home, you can estimate using today’s rates.

The starting loan length (term). The most common mortgage term is 30 years because it has the lowest monthly payments. But you can try shorter terms too, like 15 years.

The loan’s start date. It’s okay to estimate here if you don’t know exactly. But your results won’t be as precise.

Select Calculate, and you’ll get an amortization schedule where you can see how much of each payment reduces the loan balance, and how much goes to interest.