Power Calculator (P = W/t)
Power calculator: P = W/t. Find power from work or energy and time, in watts, kilowatts or horsepower.
P = Wt
How to use this calculator
- Choose the quantity you want under “Solve for”.
- Type the known values and pick their units: any combination works.
- The result updates as you type. Open “Show the steps” to see the substitution.
Power is the rate at which work is done or energy is transferred, P = W/t. One watt is one joule per second.
Convert results to kilowatts or horsepower (1 hp = 745.7 W) to compare engines, motors or athletes.
Formula
P = Wt
| Symbol | Quantity | Units |
|---|---|---|
| W | Work or energy | J, kJ, MJ, cal, kcal, Wh, kWh, eV, BTU, erg, ft·lbf |
| t | Time | s, ms, µs, ns, min, h, d, wk, yr |
| P | Power | W, mW, kW, MW, hp, PS, BTU/h, kcal/h |
Worked example
Given: W = 1 000 J · t = 10 s
P = Wt
Result: P = 100 W
Frequently asked questions
What power do I need to climb 3 m in 5 s weighing 70 kg?
W = m·g·h = 2060 J, so P = 2060/5 = 412 W.
What is the difference between kW and kWh?
kW is power (a rate); kWh is energy: 1 kW used for one hour.