The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Fill in the column titled "Period" with your payment dates.Input the month and year for the first payment loan within cell A8. This Excel spreadsheet makes it easy to view the amortization of a home loan with optional extra monthly payments. Loan amortization schedule. 3. 4, Enter values, Loan summary. Adding extra principal payments in order to pay off the loan earlier than the loan contract calls for. In this tutorial we will add this feature. This calculator will help you figure out your regular loan payments and it will also create a detailed schedule of payments. Enter your mortgage details here.