This mortgage payoff calculator is designed to help you understand the impact of making additional payments on your mortgage. This mortgage calculator will help you estimate your monthly mortgage payments based on the home price, down payment, loan term, and interest rate.1) Call the mortgage department and request an official principal payoff letter. Our free to use real estate calculator can help you estimate your monthly payment and identify a baseline of your home affordability. The mortgage payoff calculator helps you find out. Free mortgage payoff calculator to evaluate options to pay off a mortgage earlier, such as extra payments, bi-weekly payments, or paying back altogether. Mortgage Calculator. Before you buy a house, calculate how much your payments will be. Use SmartAsset's free Nevada mortgage loan calculator to determine your monthly payments, including PMI, homeowners insurance, taxes, interest and more. 3) Cancel any automatic payments in the meantime.