Calculate mechanical power from force and velocity, or from torque and rotational speed. Enter your force (N) and velocity (m/s) — or switch to the torque mode and enter torque (Nm) and speed (RPM) — and get back power in watts, kilowatts, and horsepower all at once.
Power
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Power (Kilowatts)
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Power (Horsepower)
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Power (ft·lb/s)
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Power (BTU/min)
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Mechanical power is calculated as P = F × v, where F is the applied force in Newtons and v is the velocity in metres per second. The result is in watts (W). Alternatively, for rotating systems, P = τ × ω, where τ is torque in N·m and ω is angular velocity in radians per second.
Convert RPM to angular velocity using ω = (2π × RPM) / 60, then multiply by torque: P = τ × ω. For example, a motor producing 50 N·m at 1500 RPM delivers P = 50 × (2π × 1500 / 60) ≈ 7854 W or about 7.85 kW.
Both are units of power. One mechanical horsepower equals exactly 745.69987 watts. Horsepower is commonly used for engines and motors in automotive and industrial contexts, while watts are the SI standard unit used in science and engineering.
The SI unit is the watt (W), equal to one joule per second. Other common units include kilowatts (kW), horsepower (hp), foot-pounds per second (ft·lb/s), and BTU per minute. This calculator shows results in all these units simultaneously.
Time can be found by rearranging the power formula: t = W / P, where W is work in joules and P is power in watts. For example, if a machine performs 9000 J of work at 150 W, it takes 9000 / 150 = 60 seconds.
Joules per second (J/s) is the definition of one watt. It represents the rate at which energy is transferred or work is done. So a device consuming or producing 1 joule every second has a power of exactly 1 watt.
One mechanical horsepower equals 745.7 joules per second (watts). Over a full hour, that amounts to 745.7 × 3600 ≈ 2,684,520 joules, or roughly 2.685 MJ.
Yes — the torque and RPM mode is ideal for electric motors. Enter the rated torque in N·m and the rated speed in RPM to find the shaft output power. For electrical input power calculations, you would additionally need motor efficiency.