Should I Refinance CalculatorHow much interest can you save if you refinance your mortgage? The Should I Refinance Calculator helps you find out. Enter the specifics about your current mortgage, along with your current appraised value, new loan term, rate and closing costs. The calculator will determine how much interest refinancing can save you and if you should refinance your mortgage. In addition, it will calculate the number of months to break even on closing costs with your reduced monthly payment.