The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Here is the link to my spreadsheet where you can calculate a loan over x years to be paid back monthly.It will give you the amortized payment amount. I would like to be able to calculate the remaining amount of loan due after each payment on a loan with irregular payment dates and irregular amounts. No. Due Date, Due Payment, Extra Payment (Recurring), Extra Payment (Irregular), Interest Paid, Principal Paid, Balance. 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. 13, Payment number, Payment date, Beginning balance, Scheduled payment, Extra payment, Total This report was prepared for Capital One Bank and is intended only for its specified use.