Yes, a mortgage calculator can help you buy a home by letting you see what you can reasonably afford to spend. Here are a few ways you can use the mortgage calculator to plan for your future: Change the down payment amount and home price to see how it would impact your monthly payment. See the effects shortening or lengthening the loan terms would have on your monthly payment and total interest paid. Vary interest rates to see how your monthly and total payments change based on interest rate changes. Use the amortization schedule to see how much you will pay towards your principle balance and interest balance per month over the life of your loan.