A payoff letter shows the remaining balance on your mortgage, including fees, interest, etc. Learn more about what a payoff quote is and how to request one.1) Call the mortgage department and request an official principal payoff letter. The mortgage payoff calculator helps you find out. A payoff letter provides instructions on how to pay off a loan with a lump sum before the loan term ends. Learn how payoff letters work. A mortgage payoff letter can come in two forms. One form tells borrowers the remaining principal amount and interest they have to pay to close out the loan. NerdWallet's early mortgage payoff calculator figures out how much more to pay. To begin, please fill out a claim form.