You have some extra cash and wonder whether to pay off debt or to invest it. It's a decision some make without careful consideration. But it has long term consequences. This free calculator shows you the future effects of an investment versus the effects of paying down a current debt. You need only three number: the amount available to invest, the anual interest rate on your current debt, and your investment's annual return. This free financial calculator offers integrated help, provides automatic hints, and offers easy, free, online updates.