Work and Power Calculator

Created by Bogna Szyk
Last updated: Jan 07, 2022

This work and power calculator helps you determine the mechanical power of a particular device. You can also use it to find out how much work will be performed by a machine of a given power in a certain amount of time.

If you want to calculate electric power, try our Ohm's law calculator.

Definition of work

In Physics, work performed by an object is understood as the amount of energy that needs to be supplied to move by a certain distance. For example, it can be the energy required to carry heavy bags up the stairs or the kinetic energy resulting in the movement of the body.

Generally, it is calculated as force multiplied by the displacement an object travels. Precisely speaking, it's a dot product between these two quantities. It is measured in joules (J), expressed as kg·m²/s² in SI units, or kilowatt-hours (kWh).

Speaking of joules, you might find our nm to joules converter an interesting read.

Definition of power

Power is the rate of change of work or the amount of work done in a certain amount of time. The higher the power of a device, the more work it can perform in a given time period. It is measured in watts (W), equivalent to kg·m²/s³ in SI units.

How to calculate power using the work and power calculator

  1. Determine the value of work. You can either directly type this value into our calculator or use the advanced mode to find it based on force and displacement. In this example, we will assume W = 9000 J.
  2. Determine the time in which the work will be done. Here, we can take t = 60 s.
  3. Power is equal to work divided by time. In this example, P = 9000 J / 60 s = 150 W.
  4. You can also use our power calculator to find work – simply insert the values of power and time.

For some real-life applications of power, check out the cycling wattage calculator!


How do you calculate time from power and work?

Since power is the amount of work per unit time, the duration of the work can be calculated by dividing the work done by the power.

What are the units for calculating work and power?

The unit of work is the joule (J), which is kg·m²/s² in SI units. Another standard unit of work is kWh.

The unit of power is the watt (W), which is the number of joules of work done per second.

How many joules per kJ?

There are 1,000 joules in a kJ (kilojoule). Whenever you see the letter k in front of a unit, that means the unit is multiplied by 1,000.

How many joules in 1 horsepower?

One horsepower is equal to 735.5 watts, or joules per second. So, if work is done at one horsepower for 1 second, that's equal to 735.5 joules. Multiply by the duration of the work, in seconds, to find the total energy in joules.

What is joules per second?

Joules per second is the rate of work done and is more commonly known as power. The unit for power is the watt (W), whose units are J/s.

Bogna Szyk
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