Make extra house payments. Use this calculator to see how making extra payments affects how soon you can pay off your mortgage and how much interest you pay on your home loan.The mortgage payoff calculator helps you find out. Enter your mortgage details here. Enter extra payment amount in relevant month rows. Under the Loan Information section, you will find a payoff request option that will take you to our payoff request form. Find out how to pay off your mortgage faster with our mortgage payoff calculator. Take control and achieve financial freedom sooner. Use the extra payment calculator below to help determine how advantageous it is to pay a little extra each month toward your mortgage. Homeowners can find a summary of their mortgage interest payments on Form 1098, which lenders should send out around the end of January.