Rotation Speed Converter

Convert rotational speed between RPM, RPS, rad/s, deg/s, Hz, and rev/h for motors, fans, spindles, and machinery ratings.

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Rotation speed converter Convert motor, spindle, fan, and drill speeds between RPM, revolutions per second, radians per second, degrees per second, hertz, and revolutions per hour.

Common presets

Magnitude-only converter

This tool treats rotation speed as a positive magnitude for equipment comparison. Use zero or greater values for motors, fans, turntables, spindles, and other machinery ratings.

Quick checkpoints

60 RPM = 1 RPS = 1 Hz = 2π rad/s = 360°/s. 1 RPM = 60 rev/h.

Enter a rotation speed Provide a motor or shaft speed to compare RPM, RPS, radians per second, degrees per second, and related rate units.

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Machine Rates

Rotation speed converter: RPM, RPS, rad/s, degrees per second, and hertz explained

A rotation speed converter rewrites the same spin rate in the unit your job expects. Workshop labels often use RPM, controls and physics formulas prefer rad/s, and instrumentation may report hertz or revolutions per second. Converting them cleanly matters because those labels describe the same underlying motion but not the same notation.

How rotational and angular units connect

One revolution contains 2π radians and 360 degrees. Once you know how many revolutions happen per second or per minute, every other supported unit is just a scaling step away.

That is why 60 RPM equals 1 revolution per second, 1 hertz, about 6.2832 rad/s, and 360 degrees per second. The object is not spinning differently; only the reporting convention changes.

1 revolution = 2π rad = 360°

Links revolution-based and angle-based rotation units.

RPM = Hz × 60

Moves between cycles per second and cycles per minute.

rad/s = Hz × 2π

Converts a rotational frequency into angular speed.

Rotation speed is not the same as linear surface speed

Two shafts can share the same RPM while their rim speeds are very different if the radii are different. Linear speed depends on both angular speed and radius, so RPM alone is not enough to describe belt speed, wheel speed, or tangential tool velocity.

That distinction matters in motors, turntables, grinders, and fans. Use this converter for the spin rate itself, then pair the result with a radius if you need a linear-speed calculation.

Which unit should you use?

RPM remains the most familiar unit for motors, engines, fans, drills, and machine tools because it matches how manufacturers label rotational equipment. Hertz and revolutions per second are compact for instrumentation and signal-style reporting, while rad/s is the SI-friendly choice when the value needs to enter a physics or controls formula.

Degrees per second can be handy in robotics, camera motion, or navigation-style contexts where angular sweep is easier to visualise in degrees than radians.

Further reading

Frequently asked questions

How many RPM are in 1 hertz?

One hertz equals 60 RPM because hertz counts revolutions per second and RPM counts revolutions per minute. Multiplying by 60 converts seconds to minutes.

 Why is rad/s different from RPM?

RPM counts full revolutions per minute. Rad/s measures angular change directly in radians per second. Since one revolution equals 2π radians, the two units differ by both the 2π factor and the time-unit conversion.

 Can two machines with the same RPM have different tip speeds?

Yes. Linear surface speed depends on radius as well as angular speed. A larger wheel or blade moving at the same RPM covers more distance per second at its rim.

 Is hertz the same as revolutions per second?

For simple rotational frequency, yes. Both describe one full revolution each second. The difference is mostly naming and context rather than magnitude.

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