By Zencalcy Editorial TeamLast reviewed About us
A shaft transmits power when torque acts through a rotation. The power is torque times angular speed, so a fast-spinning motor can deliver the same power as a slow, high-torque engine. This is why gearboxes trade speed for torque.
Power delivered by a torque at an angular speed.
P = τ ω
P is power in watts, τ is torque in newton-metres and ω is angular speed in rad/s. One watt equals one N·m per second.
| Symbol | Meaning |
|---|---|
| P | Rotational power, in watts. |
| τ | Torque, in newton-metres. |
| ω | Angular speed, in rad/s. |
The power is 50 × 10 = 500 W, about 0.67 hp. Doubling the speed at the same torque doubles the power, which is what a gearbox does when it shifts up.
Continue with the SHM Acceleration Calculator, SHM Displacement Calculator, or the SHM Velocity Calculator — or browse more rotational and periodic motion tools and all physics calculators.
No. Both are energy per second. The rotational form replaces force with torque and speed with angular speed.
Results are computed from the standard equations of classical mechanics. Unit conversions use the SI definitions published by NIST. Air resistance is ignored unless the calculator names a drag model.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026