Angular velocity converter
Convert rpm to rad/s and back, and watch a wheel spin at the rate you typed.
That's about the same as a power drill. On a 30 cm wheel the rim moves at about 169.6 km/h.
What it means
How fast does that spin?
Rim speed assumes a wheel 30 cm across. A bigger wheel at the same rpm moves faster at the edge.
Every unit
Your rotation speed in every unit
Learn
Three things worth knowing
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rad/s ≈ rpm ÷ 9.55
The exact factor is π/30. A 3,000 rpm engine turns at 314 rad/s, and 1,500 rpm is almost exactly 157.
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Why radians simplify everything
One radian is the angle where arc length equals radius. Choose that and rim speed, energy and acceleration formulas lose all their constants.
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rpm is not rim speed
A grinding disc at 10,000 rpm is dangerous because of its diameter. Rim speed is what the material feels, and it grows with the radius.
Shortcuts
Popular rotation speed conversions
Background
About rotation units
Engineers say rpm, physicists say radians per second. One revolution is 2π radians, so the conversion is rpm × π ÷ 30.
Radians win in formulas because rim speed is simply v = ωr, with no conversion factor.