The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Loan amortization schedule. 3.4, Enter values, Loan summary. Fill in the "Period" column. Fill in the column titled "Period" with your payment dates. This Excel spreadsheet makes it easy to view the amortization of a home loan with optional extra monthly payments. Does anyone know how to calculate the principal and interest payments after a one time extra principal payment on a mortgage in excel? Fill. Create an Account or Sign In. × Close. Track your portfolio in the most efficient way. Bond Search; Watchlist; Excel ADD-IN.