Power
Power P = W / t and P = F · v: find power, work, time, force or speed with conversion of kW, hp and kWh and a solution.
Numbers can be decimals (2.5), fractions (1/3) or scientific notation (1.5e3). Pick any units — the calculator converts them to SI.
The power calculator finds power from work and time or from force and speed, as well as work, time, force and speed. You can enter kilowatts, horsepower, kilowatt-hours and km/h — everything is converted to SI.
Power formulas
| Known | Formula |
|---|---|
| Work and time | P = W / t |
| Force and speed | P = F · v |
Power is the work done per unit time. Its unit is the watt: 1 W = 1 J/s. The second formula follows from the first: at constant speed W = F · s, and s / t = v.
| Unit | Value |
|---|---|
| 1 kW | 1000 W |
| 1 metric horsepower | 735.49875 W |
| 1 kWh | 3,600,000 J |
Example 1. A lift does 36 kJ of work in 1 minute: P = 36,000 J / 60 s = 600 W.
Example 2. A 2 kW heater runs for 3 h: W = 2 kW · 3 h = 6 kWh.
Example 3. A car moves at 72 km/h = 20 m/s with a 500 N driving force: P = 500 · 20 = 10,000 W = 10 kW.
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