Transcript: What does RPM stand for? RPM stands for "revolutions per minute." It's a measure of how fast the engine is spinning. In general, the faster an engine spins, the more power it makes. An engine works by burning air and gas to push the pistons down. That force makes the crankshaft spin, which is what ultimately drives the wheels of the car. How much force is transmitted to the crankshaft is called torque. Horsepower is a measure of work over a period of time.
At higher RPM, the engine is burning more air and fuel. That means it makes more power and consumes more gas. The tachometer usually displays RPM in thousands. So if the tachometer is pointing to the "2," it's turning at 2,000 revolutions per minute. Drivers with manual transmissions use the tachometer as a reference point for when to shift. Not enough RPM could make the engine stall. Too many could hurt the engine.
The engine's RPM limit is displayed on the tachometer as a red area known as "redline." Exceeding this limit could cause severe engine damage. It's generally most efficient to shift at lower RPM. Every car is different, but your owner's manual may have guidance on efficient shift points.