The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. This Microsoft Excel template illustrates how to create a loan amortization schedule, as well as dealing with additional payments and variable interest rates.This example teaches you how to create a loan amortization schedule in Excel. 1. We use the PMT function to calculate the monthly payment on a loan. Looking for a flexible free downloadable mortgage calculator built in Excel? Try this free feature-rich mortgage calculator today! An amortization schedule is a table format that lists periodic payments on a loan or mortgage over a period of time. This spreadsheet-based calculator creates an amortization schedule for a fixed-rate loan, with optional extra payments. Create a Loan Amortization Schedule in Excel and include optional extra payments. An easy-to-use amortization calculator.