The mortgage payoff calculator helps you find out. This tool allows you to perform standard mortgage calculations.Click Apply Now to start your loan application. As you complete the application, please use your best estimate if documentation is not available. Use this free Texas mortgage calculator to estimate your monthly mortgage payments and annual amortization. Calculate your monthly payment and see how the principal is paid over time. FORMS. download and print forms. This spreadsheet creates an amortization schedule for a fixed-rate loan, with optional extra payments. Use SmartAsset's free Texas mortgage loan calculator to determine your monthly payments, including PMI, homeowners insurance, taxes, interest and more. The mortgage payoff calculator helps you find out.