Mortagage Calculator One of the major benefits of mortgage calculators is to help you figure out exactly what you can afford. While most people understand what they can afford as monthly payments, they are generally unclear on how interest and everything else works in terms of numbers. With the help of mortgage calculator, you can have the luxury of playing with the numbers: amount of deposit, interest rate, and loan term to figure out what you can afford. You can also compare the different mortgage offers you get from different banks and plan for a better refinance offer.