Which dashboard gauge shows engine RPM?

The tachometer is the dashboard gauge specifically designed to measure the engine's RPM (revolutions per minute). This is crucial for drivers, especially those operating heavy vehicles, as it helps maintain optimal engine performance and energy efficiency. By monitoring the RPM, the driver can determine the appropriate gear to be in, ensuring that the engine operates within its ideal power band and preventing potential damage from over-revving.

The other gauges serve different purposes: the speedometer shows the vehicle's speed, the fuel gauge indicates the level of fuel in the tank, and the temperature gauge monitors the engine's temperature. While all these gauges provide important information regarding the vehicle's operation, it is the tachometer that directly relates to engine performance in terms of RPM measurement.