Mortgage Calculator - Version 1.3 A dual-mode calculator which is always right there when you need it. The two modes are standard arithmetic and a mortgage/loan amortization calculator. Enter the initial amount, time period and interest rate and the calculator will give you a comprehensive listing of your repayments throughout the lifetime of the loan, showing principal and interest repayments for each month. This can be copied into other programs for further examination. Test the effect of changing interest rates on your payments and compare offers from different companies.