Use the calculator below to estimate your monthly loan payments for the mortgage you plan to borrow. Enter the number of payments for the term of the loan, (360 for a 30 year mortgage). Enter the current Interest Rate (i.e. .08) and the amount (Principal) you wish to borrow. Click on Compute. Your estimated loan payment will be calculated for you. Taxes, insurance and homeowners association fee, if any, will make your monthly cost of ownership higher.