Duration is a powerful risk hedging tool and is measured in number of years. A bond with a duration of 4 years can be used to perfectly hedge a liability arising after 4 years. You can use this calculator to estimate the duration of your bond/debenture. You can also simulate what kind of a bond you need to purchase to hedge a liability arising after a particular number of years. Duration of a deep discount bond is exactly equal to its maturity period. For all coupon bonds duration is less than the term to maturity. Hedge your risks effectively and scientifically.