The mortgage payoff calculator helps you find out. We provide the mortgage and tax service companies tax statement information upon request, so your mortgage company should receive your tax information.1) Call the mortgage department and request an official principal payoff letter. 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. A payoff request can be created and mailed for free. How long does it take to obtain a payoff? Use this free Arizona mortgage calculator to estimate your monthly mortgage payments and annual amortization.