If you need to calculate an amortization schedule for a mortgage or other loan, REIA offers a downloadable Microsoft Excel spreadsheet that will do just that.

Click here to download the spreadsheet.

If you prefer, you can visit HSH Associates website and use their web amortization calculator by clicking here. 
Try using the optional features, such as the "Additional Principal Prepayment Amount" and see how much interest is saved by even a small prepayment each month!