Mortgage Comparison Calculator View Calculator Calculate and compare (formatted side by side) the monthly payments for up to 4 mortgage loans. Enter your sale price, any down payment you're making, the interest rate and the term of each loan. This calculator will then show you the monthly principal and interest payment, the total amount of interest you will pay and the total amount of money you will spend over the life of each loan. You can also enter the points and other closing costs and roll those into your loans. You can even enter an additional payment amount you intend to pay each month to work down your principal and the calculator will show you the anticipated payoff time. Learn more about putting this calculator or other calculators on your website.