Use the following formulas to show the total payment, interest portion of the payment, and principal portion of the payment. This Microsoft Excel template illustrates how to create a loan amortization schedule, as well as dealing with additional payments and variable interest rates.Create a loan summary and payment schedule based on the terms of the initial loan with this loan amortization schedule template. In this tutorial we're going to learn how to build a simple loan calculator application in Excel. Download the amortization schedule from Microsoft. 2. Open the template in Excel. 3. Note: The purchased version of this document includes a Loan Amortization Schedule Calculator (in Microsoft Excel format). You can get quotes from up to five lenders in minutes through LendingTree. Use this calculator to find out how much money you might be able to borrow with a home equity loan and how much it might cost. Check out the web's best free mortgage calculator to save money on your home loan today.