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. This Excel spreadsheet makes it easy to view the amortization of a home loan with optional extra monthly payments. Fill in the "Period" column. Fill in the column titled "Period" with your payment dates. Does anyone know how to calculate the principal and interest payments after a one time extra principal payment on a mortgage in excel? Please contact UHC for any special accommodations. Detailed Use of Funds: Please complete all pages of the Excel template found at: Please see. Budget Detail document attached in the email.