Cubic feet per minute or CFM measures the volumetric velocity of air passing through the blower in one minute. In other words, the speed of your device blows off leaves and debris depends on this value. However, the air volume does not make sense if it does not move fast enough; therefore, MPH is also important. In other words, this is the amount of air pushed through the nozzle of the blower. For example, a 300 cubic meter leaf blower blows 300 cubic feet of air every minute through a nozzle. A higher CFM number means that the blower will have more power to move things. Some blowers have a very high CFM rating.