RPM stands for rotations per minute. RPM helps to signify the acceleration of the vehicle. They are used to measure the number of times an engine crankshaft rotates within one minute.  The RPM gauge on the instrument cluster of your vehicle can tell you how fast the engine crankshaft is rotating at any given moment. There are a number of reasons why RPM is important. One of them is the fact that it notifies the driver about the number of rotations made by the crankshaft in a minute. It also helps to get better fuel economy as high RPMs mean that more fuel is used while on the other hand, while low RPMs are good for better fuel economy.