Make math easier with these free calculator templates. Create automatic loan amortization schedule table with PMT, IPMT, PPMT formulas in Microsoft ExcelEnter your mortgage details here. Enter extra payment amount in relevant month rows. Create a loan amortization schedule with additional payments. This works for mortgages, car loans, student loans, any type of loan. The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. This amortization calculator shows the schedule of paying extra principal on your mortgage over time.