See the principal balance change as payments are made. This will show you how much you will owe on your house in “X” amount of years. Also, see how much of your payment is being applied to the principal and how much is being applied to the interest. Most of your payment in the beginning of the loan pays the interest of the loan.
This calculator will help you to decide whether or not you should refinance your current mortgage at a lower interest rate. This calculator will calculate the monthly payment, net interest savings, and the time it will break even on the closing costs.