Mortgage calculators are used to help a current or potential real estate owner determine how much they can afford to borrow to purchase a piece of real estate. Mortgage calculators can also be used to compare the costs or real interest rates between several different loans, determine the impact on the length of the mortgage loan of making added principal payments or bi-weekly instead of monthly payments.

A mortgage calculator is an automated tool that enables the user to quickly determine the financial implications of changes in one or more variables in a mortgage financing arrangement. The major variables include:

When purchasing a new home most buyers choose to finance a portion of the purchase price via the use of mortgage. Mortgage calculators make answers to questions regarding the impact of changes in mortgage variables available to everyone.

A User can use an online mortgage calculator to see how much property he can afford. A lender can compare his total monthly income and total monthly debt load. A mortgage calculator can help a user add up all his income sources and compare this to his monthly debt payments. It can also factor in a potential mortgage payment and other associated housing costs (property taxes, homeownership dues, etc.). The user can test different loan sizes and interest rates.