A standard, amortizing mortgage payment is comprised of two parts - principal reduction and interest repayment. Or, you can use this online mortgage calculator. All you need is a few formulas - which are shown below - and your favorite desktop spreadsheet software. Having your own record that you can update anytime and return to for reference is a good way to keep you financially aware of your mortgage obligations as well as organize payment schedules. There are many mortgage amortization calculators available online but it is also best to have your own mortgage payment amortization schedule and record. This is to ensure that their mortgage payments are up-to-date and at the same time to make adequate allocations to their finances and even to maintain savings. Amortization schedule for personal loans with interest and missed payment calculations. Free customizable iWork loan templates for Mac Pages and Numbers. Making the Mortgage Calculator interactive with regard to payments during the term of the mortgage requires reworking.