This guide will help you learn mortgage math, allowing you to confidently calculate how much you need to pay off your mortgage. 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. Create a Loan Payoff Letter online and download it as a PDF or Word document. Customize and print a blank Loan Payoff Letter for free. The Senate met at 10 a.m.