A mortgage calculator is an online calculating tool provided as an extra service in some of the real estate or financial companies’ websites which can be used to plan your property investments.  The calculator bases its calculation on the property value, the down payment, the property tax, the interest rate, the loan duration, and the start date of the loan.  The outcome is an amortization table, which is a table showing the loan break-up month by month. It has a separate column showing the interest part of the installment and principal amount, as well as the total.  This makes it easier to calculate your equity in the property and find out the mortgage calculators total interest paid as time passes.  This table can also help you plan wisely for your loan like setting dates when you can pay a larger sum towards the loan, such as if you receive an end of year bonus from your occupation, or planning ahead for different events such as sending your child to college.