1) Call the mortgage department and request an official principal payoff letter. This mortgage payoff calculator is designed to help you understand the impact of making additional payments on your mortgage.You owe the balance plus whatever interest has accrued since that statement. And there may also be a fee when you pay it off. It lays out each fee and dollar still due before you completely pay off your mortgage. Here's how it works. The mortgage payoff statement is a document that provides a comprehensive breakdown of the remaining balance on a mortgage. How can I request a payoff statement? Contact your servicing bank (where you make your monthly mortgage payments) and request a payoff statement. I'm selling my house with a closing date of January 9th.