Power Calculator

Calculate mechanical power from work and time, or from force and velocity.

About Power Calculator

Power is the rate of doing work. The force-times-velocity form is more useful for machines, because it shows that a fixed power output trades force against speed — the basis of every gearbox. A motor rated in kilowatts can deliver high force at low speed or low force at high speed, but never both, which is why gearing exists.

Formula

Power

P = W ÷ t, and equivalently P = F v

P: Power in watts
F v: Force times velocity, the instantaneous form

Worked example

With the default values below, Power Calculator returns Power From Work and Time of 500.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Work doneminimum 0 J: 5,000 J
Time takenminimum 0.01 s: 10 s
Forceminimum 0 N: 500 N
Velocityminimum 0 m/s: 10 m/s

Results

Power From Work and Time: 500.00 W
Power From Force and Velocity: 5,000.00 W
Power: 0.5000 kW
Power: 0.6705 hp
Energy Consumed in an Hour: 0.5000 kWh

Step by step

1Values used
2Power
3Power From Work and Time= 500.00 W
4Power From Force and Velocity= 5,000.00 W
5Power= 0.5000 kW
6Power= 0.6705 hp
7Energy Consumed in an Hour= 0.5000 kWh

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Power calculated?

P = W ÷ t, and equivalently P = F v Power is the rate of doing work. The force-times-velocity form is more useful for machines, because it shows that a fixed power output trades force against speed — the basis of every gearbox.

Why does Power matter?

A motor rated in kilowatts can deliver high force at low speed or low force at high speed, but never both, which is why gearing exists.

What values do I need to enter?

This calculator takes 4 inputs: Work done, Time taken, Force, Velocity. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.