The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Here is the link to my spreadsheet where you can calculate a loan over x years to be paid back monthly.It will give you the amortized payment amount. 1) Download and open ExcelDemy's file in the Irregular Extra Payment tab. This Excel spreadsheet makes it easy to view the amortization of a home loan with optional extra monthly payments. I am trying to create a loan repayment spreadsheet in Excel 2003. It needs to be flexible with regard to payment amounts and payment intervals. In this tutorial we will see how to create an amortization schedule for a fixed-rate loan using Microsoft Excel and other spreadsheets. Want to know the impact of "extra payments" on your mortgage? Check out this easy to use Excel mortgage calculator.