Free Mortgage Calculator is a simple program that was developed to make it easy for the user to calculate mortgage payments The program allows you to calculate a mortgage based on several different options including Loan amount, APR, and Down payment amount. The user only needs to edit three fields in order to calculate mortgage payments for a given fixed rate mortgage. The program also allows a user to enter a annual lump sum, payment to see how it will effect their monthly mortgage payments. It also allows the user to choose in between weekly bi-monthly or monthly mortgage payments.