How it works
Convert frequencies used in electronics, radio and audio (hertz through terahertz) and rotational speeds used for engines and motors (RPM, radians per second, degrees per second).
One hertz is one cycle per second, so 60 RPM is 1 Hz. Angular velocity in radians per second is 2π times the frequency in hertz, because one full revolution is 2π radians.
Formula
Hz = rpm ÷ 60; ω (rad/s) = 2π × Hz
Questions people ask
How do I convert RPM to Hz?
Divide by 60. A motor spinning at 3,000 RPM turns 50 times per second, or 50 Hz.
What is the relationship between frequency and period?
The period is the reciprocal of frequency: T = 1/f. A 50 Hz signal has a period of 0.02 s (20 ms).
Why do AC motors run at 1,800 or 3,600 RPM?
On 60 Hz power, a 2-pole synchronous motor turns at 3,600 RPM and a 4-pole motor at 1,800 RPM. Induction motors run slightly slower than these synchronous speeds.