Thinking about purchasing a new car? Use our new Car Loan Calculator to estimate your monthly car payment!

How to Read an Rpm Gauge

by Colin McGrath

The rpm (revolutions per minute) gauge is an integral part of most vehicles. Whether you are operating your vehicle in a standard fashion or you are attempting to troubleshoot a problem, the rpm gauge can come in handy. Revolutions per minute refers to how many full revolutions something has made, such as an engine in your car. In an automobile, the rpm gauge is referred to as a tachometer and it is often found on the driver's dashboard.

Look at your rpm gauge and notice that it is composed of a needle and ascending numbers from left to right. The needle moves as the rpm change to indicate the current speed of your engine.

Inspect your rpm gauge to see if it has been scaled down. For example, most rpm gauges in cars will say something along the lines of "RPM x1,000."

Multiply the number indicated by your rpm gauge needle with the proper scale if necessary. If your scale was 1,000 and your needle pointed at the number 3 on your gauge, then your total rpm would be 3,000.


  • You can use your rpm gauge to tell if your car is idling too high. This means that even when you are not pressing the gas pedal, the engine will rev and you will see your needle move to a higher number.

Items you will need

About the Author

Colin McGrath began writing professionally in 2004. He's written reviews for and has also published in leading academic journals such as "Optics Express" and "Engineering Letters." McGrath graduated from the University of Washington in Seattle with a Bachelor of Science in physics and a Bachelor of Science in applied mathematics.

More Articles

Photo Credits

  • compte-tours 2 image by Frédéric Prochasson from