Power Calculator
Find power output from the amount of work done and the time it takes.
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s
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Work and time
W = 5,000 J, t = 10 s - 2
Power = Work ÷ Time
5,000 ÷ 10 = 500One watt equals one joule per second.
Formula
How this is calculated
You enter two values: the work done (or energy transferred), measured in joules (J), and the time taken to do it, measured in seconds (s). Work is the total energy moved — for example lifting a box or running a motor — while time is simply how long that transfer lasts. Both must be plain SI quantities for the result to come out in standard units.
The calculator divides work by time to get power: P = W ÷ t. Because one joule per second is defined as one watt, the answer appears directly in watts (W). The same number is then rescaled for convenience: dividing by 1000 gives kilowatts (kW), and dividing by 745.6999 gives mechanical horsepower (hp), the traditional unit used for engines and motors.
The model assumes work is delivered at a steady average rate over the whole interval, so the result is the mean power, not the instantaneous peak. Time must be greater than zero — a zero or negative time leaves the result blank, since dividing by zero is undefined. Sign and magnitude of work pass through unchanged, so negative or very large inputs are reported as entered.
Examples
| Input | Result |
|---|---|
| W = 5000 J, t = 10 s | P = 500 W ≈ 0.67 hp |
About this calculator
Power is the rate at which work is done or energy is transferred: P = W / t. With work in joules and time in seconds, power is measured in watts (W), where one watt equals one joule per second.
Two machines can do the same amount of work, but the one that completes it faster delivers more power. Mechanical horsepower, a traditional unit still common for engines and motors, equals 745.6999 watts. This calculator also reports kilowatts for larger power figures.
Frequently asked questions
Power equals work divided by time: P = W / t. Using joules and seconds gives the answer in watts.
Divide the power in watts by 745.6999. For example, 745.6999 W equals exactly 1 mechanical horsepower.
Work is the total energy transferred, while power is how fast that energy is transferred. Doing the same work in less time means greater power.
Also known as
TG we-Calculate Editorial Team. (2026). Power Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/power-calculator
TG we-Calculate Editorial Team. "Power Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/power-calculator.
TG we-Calculate Editorial Team, "Power Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/power-calculator
@misc{wecalculate_power_calculator, title = {Power Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/power-calculator}}, year = {2026}, note = {TG we-Calculate} }
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