NerdWallet's early mortgage payoff calculator figures out how much more to pay. The mortgage payoff calculator helps you find out.Use the extra payment calculator below to help determine how advantageous it is to pay a little extra each month toward your mortgage. Accelerated Debt Payoff: The extra payment each year reduces the principal balance faster, which means less interest accrues over time. If you write to ask how much it costs to pay off your mortgage, the servicer generally has seven business days after receiving your request to answer you. A mortgage payoff letter or payoff statement is an itemized document that shows the balance that you must pay to close your loan. Additional principal payment. Your proposed extra payment amount per month. You will need to send the check to the address on your payment billing statement. Bill Fee" and on the Annual Escrow Analysis.