Power Calculator
Compute power as the rate of doing work, P = W / t, with results in watts, kilowatts, and horsepower.
Inputs explained
- Work / energy (J) — The work done or energy transferred, in joules.
- Time (s) — The time over which the work is done, in seconds.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: Doing 1,000 joules of work in 10 seconds requires 100 watts of power — about 0.134 horsepower.
Frequently asked questions
Why does the same amount of work require different power depending on time? Power measures the rate of doing work, P = W/t, so doing 1,000 joules of work in 10 seconds needs 100 watts, but doing the same work in 1 second would need 1,000 watts — the total work stays fixed while power scales inversely with time.
How is horsepower calculated from watts? The calculator converts using the mechanical horsepower definition of about 745.7 watts per horsepower, so 100 watts comes out to roughly 0.134 horsepower.
Is the Power Calculator free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Work / energy (J), Time (s). Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the Power Calculator is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.