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Multiple conversions
To convert from rotation per minute (rpm) to millihertz (mHz), use the following formula:
To convert from rotation per minute (rpm) to hertz (Hz), use the following formula:
To convert from rotation per minute (rpm) to kilohertz (kHz), use the following formula:
To convert from rotation per minute (rpm) to megahertz (MHz), use the following formula:
To convert from rotation per minute (rpm) to gigahertz (GHz), use the following formula:
To convert from rotation per minute (rpm) to terahertz (THz), use the following formula:
To convert from rotation per minute (rpm) to degree per second (deg/s), use the following formula:
To convert from rotation per minute (rpm) to radian per second (rad/s), use the following formula:
Simply put, rotations per minute (RPM) measures the speed at which something is spinning.
It counts the number of full turns an object completes in one minute. From car engines to computer hard drives, RPM is a key indicator of performance and speed.
The concept of RPM (rotations per minute) gained popularity during the Industrial Revolution, thanks in large part to Scottish engineer James Watt.
While developing his steam engine, Watt needed a way to compare its power output to that of a horse. To do this, he determined how many times a horse could turn a mill wheel in one minute.
He utilized this rotational measurement to help establish the definition of horsepower. As a result, RPM became a crucial metric for quantifying the performance and work capacity of mechanical engines—a practice that continues to this day.
You encounter RPM every day in common technology.
In your car, the tachometer displays the engine's speed in rotations per minute, indicating how fast the crankshaft is spinning. A higher RPM generally means more power is being produced.
Computer hard disk drives (HDDs) also use RPM to measure their performance; a 7200 RPM drive can read and write data faster than a 5400 RPM drive.
RPM ratings, which denote motor speed and efficiency, are also found on household appliances such as blenders, washing machines, and fans.
Although RPM is a common unit, physics and engineering often use hertz (Hz) for frequency and radians per second (rad/s) for angular velocity.
The conversion is straightforward:
To Hertz (Hz): Because a minute has 60 seconds, you divide the RPM value by 60.
To Radians per Second (rad/s): One complete rotation is equivalent to 2π radians. To convert RPM to radians per second, multiply the RPM value by 2π, then divide by 60.