Definition: The Mortgage Tax Deduction Calculator is a financial tool that calculates and displays the mortgage interest deductions for individuals who are entitled to the Federal Taxable Interest Deduction (FTED) under their home loan. It shows how much money can be deducted from the principal amount of your home loan, based on your expected property value at the time of closing. The word 'mortgage tax deduction calculator' is a tool that helps users calculate and track their mortgage interest deductions to determine if they're eligible for the federal taxable interest deduction under their home loan.