Debt reduction calculator is an online personal finance assessment tool to calculate how many months are required to pay off the debt with the extra monthly payment towards the principal amount and the total interest. The Debt balance, Annual interest rate, monthly payment against debt now and the new monthly payment against debt with extra amount are the key terms to calculate the total number of months and payments required to clear the debt. Thus you can compare how much amount of interest you can save on the borrowed principal by increasing monthly repayment amount