The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Fill in the "Period" column.Fill in the column titled "Period" with your payment dates. Calculating Payment Amount, Principle, Extra Payments and Interest-based on Term of Loan (Excel Spreadsheet. This Excel spreadsheet makes it easy to view the amortization of a home loan with optional extra monthly payments. This calculator will help you figure out your regular loan payments and it will also create a detailed schedule of payments. An amortization calculator helps you understand how fixed mortgage payments work. NerdWallet's early mortgage payoff calculator figures out how much more to pay. Payment, Total Extra Payments, Total Savings, Amortization Period.