This spreadsheet creates an amortization schedule for a fixed-rate loan, with optional extra payments. Microsoft Excel Mortgage Caculator XLS Worksheet.This spreadsheet is an allinone home mortgage calculator. It lets you analyze a fixed or variable rate home mortgage. Vertex42 is a popular online resource for a variety of Excel templates and spreadsheets. Use financial formulas like PMT() along with the List. This calculator will help you figure out your regular loan payments and it will also create a detailed schedule of payments. This amortization calculator returns monthly payment amounts as well as displays a schedule, graph, and pie chart breakdown of an amortized loan. Make math easier with these free calculator templates.