A mortgage payment calculator is an online tool that helps you find out what your monthly installment on a mortgage would be. Of course you could go directly to the bank and apply, but if you are still in the planning phase, then this is a good way to make a decision. If we assume that you are currently renting, you are still young and just started on your career path, wouldn’t you like to own your own home one day? The time to start saving for that home is now, but you don’t need to save up the entire amount, just the down payment which could range from 10% to 30%. The more your down payment, the less the total interest payment would be which means you might also get a better interest rate to start with.  With the calculator, you can estimate the value of the home you can afford and how to keep your rent payment equal to your mortgage payment. This way there is no financial stress and no rearranging your life around the loan.