The mortgage payoff calculator helps you find out. 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.Depending on your lender, you may have to sign in to an online account, call a helpline, or send a formal letter to start the request process. A mortgage payoff statement details the total amount needed to fully pay off a loan as of a specific date. Check out the payoff instructions on the Payoff Statement. But there are some things you should understand before making an additional lump sum payment on your mortgage in Washington.