Duration is a measure of the sensitivity of the price of a bond or other debt instrument to a change in interest rates. It is calculated as the weighted average time until maturity of all cash flows from the bond. The higher the duration, the more sensitive the price will be to changes in interest rates.This can be both good and bad for investors, as it means that they can earn more money if interest rates rise, but it also means that they could lose money if interest rates fall. Duration is an important tool for investors to use when making decisions about what bonds to buy or sell.