This loan payment calculator will estimate the mortgage payment for different interest rates and loan amounts. You can compare the loan payment for 5, 10, 15, 20, 30, 35 and 40 year terms. This calculator will also calculate a biweekly and interest only loan payment. Do interest rates matter? Less than you think. Enter the "lower" interest rate in Mortgage Payment 1 and the higher interest rate in Mortgage Payment 2 and click the Compare Payments box. See the current interest rates below. You can also compare home equity payments with this calculator.