Refinance Analysis Calculator Mortgage Refinancing Calculator This calculator will help you to decide whether or not you should refinance your current mortgage at a lower interest rate. Not only will this calculator calculate the monthly payment and net interest savings, but it will also calculate how many months it will take to break even on the closing costs. Enter the principal balance of your mortgage: (call your mortgage lender and ask for the current payoff amount) Enter the amount of your monthly mortgage payment (Principal & Interest Only): Enter your mortgage's current interest rate: Enter interest rate you will be refinancing at: Enter the number of years you will be refinancing for: Enter the closing costs percentage points dollar amount : (Typically, # of points is "2" or dollar amount is .02 times the principal) Would you like to finance the closing costs? No Yes