How to Use Rotational Speed Calculator
The Rotational Speed Calculator converts RPM into every common spin-related quantity.
- Enter Rotational Speed (RPM) — Use the value from a motor nameplate, tachometer, or design spec.
- Enter the Radius (Optional) — Provide the radius of the rotating part in mm, cm, or m if you also want linear speed.
- Read All Results — The calculator outputs RPS, angular velocity (rad/s), and three linear-speed conversions (m/s, m/min, km/h).
Formula & Theory — Rotational Speed Calculator
ω = 2π × RPM ÷ 60 [rad/s]
RPS = RPM ÷ 60 [rev/s]
v = ω × r [m/s]
v_kmh = v × 3.6 [km/h]
v_mmin = v × 60 [m/min]| Symbol | Meaning |
|---|---|
| RPM | Revolutions per minute |
| RPS | Revolutions per second |
| ω | Angular velocity in radians / second |
| r | Radius of the rotating part |
| v | Tangential / linear speed |
Why 2π?
One full revolution sweeps an angle of 2π radians. Multiplying RPS by 2π converts revolution-based speed to radian-based angular velocity, the standard unit in physics and engineering.
Use Cases for Rotational Speed Calculator
- Manufacturing & Machining — Convert spindle RPM into surface cutting speed for milling, drilling, and turning.
- Conveyor Design — Translate drive-roller RPM into belt speed for layout and throughput calculations.
- Automotive Engineering — Compute wheel surface speed from RPM for brake testing and tire wear analysis.
- Fans & Pumps — Predict tip speed limits to avoid noise and stress.
- Physics Homework — Help students see how RPM, rad/s, and m/s are connected.
The Rotational Speed Calculator turns RPM into the exact unit your project needs, instantly.