The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. 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. Fill in the column titled "Period" with your payment dates. Input the month and year for the first payment loan within cell A8. Enter your mortgage details here. Enter extra payment amount in relevant month rows. Loan Amortization Schedule, This spreadsheet creates an amortization schedule for a fixed-rate loan, with optional extra payments. Here is the link to my spreadsheet where you can calculate a loan over x years to be paid back monthly.