Power tells you how quickly energy is used or transferred. Climbing stairs quickly takes more power than climbing slowly, though the work is the same.
How to use the Power Calculator
- Work or energy
- Time
- Want to work backwards? Type a value into Power and Time is calculated for you.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Divide the work or energy by the time taken.
Inputs explained
| Field | What to enter |
|---|---|
| Work or energy | Units: J, kJ, MJ, cal, kcal, Wh … |
| Time | Units: s, min, h |
Example values
How the main result changes when Time changes and everything else stays at the example values above:
| Time (s) | Power (W) |
|---|---|
| 5 | 1,000 |
| 7.5 | 666.67 |
| 10 | 500 |
| 12.5 | 400 |
| 15 | 333.33 |
| 20 | 250 |
Formula
P = W ÷ tWorked example
Inputs — Work or energy: 5,000 J; Time: 10 s.
Results — Power = 500 W.
Frequently asked questions
How many watts is one horsepower?
About 745.7 W (mechanical horsepower).
What is the difference between power and energy?
Energy is the total amount; power is the rate.
What formula does the Power Calculator use?
P = W ÷ t.
Can I work backwards from the result?
Yes. Type the result you want into Power and the calculator finds the matching time.