What is the formula for work done?

Work is W = F × d × cos θ, where F is force in newtons, d is the displacement in metres, and θ is the angle between the force and the direction of motion. At θ = 0 the cosine is 1, so W = F × d.

How do I calculate power?

Power is the rate of doing work: P = W / t in watts, or equivalently P = F × v when a force F moves an object at constant velocity v. One horsepower equals 745.7 watts.

Why is there a cosine in the work formula?

Only the component of force along the direction of motion does work. The cos θ term extracts that component, so a force perpendicular to the motion (θ = 90 degrees, cos θ = 0) does zero work.

What units does the calculator use?

SI units throughout — force in newtons (N), distance in metres (m), time in seconds (s), and velocity in metres per second (m/s). Results are work in joules (J) and power in watts (W).

How do watts relate to horsepower?

One mechanical horsepower equals 745.7 watts. The calculator shows the power result in horsepower alongside watts for an intuitive comparison.

What is the difference between work and power?

Work is the total energy transferred (joules). Power is how fast that energy is transferred (joules per second, or watts). The same work done in less time means more power.

Is anything uploaded?

No — all calculations happen in your browser and nothing leaves your device.

Work and Power Calculator

Work and power calculator

This calculator solves two core mechanics quantities from classical physics: work (the energy a force transfers) and power (how fast that energy is transferred). It is built for students and anyone checking homework or engineering estimates, and it works in SI units throughout.

How it works

Work is calculated from force, displacement, and the angle between them:

W = F × d × cos θ

measured in joules. The cosine term keeps only the part of the force that acts along the direction of motion, so a force at right angles does no work. Power can be found two ways — as work done over time, or directly from force and velocity:

P = W ÷ t or P = F × v

both in watts. The tool also converts watts to horsepower (1 hp = 745.7 W) for reference.

Quantity	Formula	Unit
Work	W = F × d × cos θ	joule (J)
Power (from work)	P = W ÷ t	watt (W)
Power (from velocity)	P = F × v	watt (W)

Example

A 50 N force pushes a box 4 m in the direction of motion (θ = 0): W = 50 × 4 × cos 0 = 200 J. If that takes 8 seconds, the power is P = 200 ÷ 8 = 25 W, which is about 0.034 hp.

Choose a mode, type your values, and read the answer instantly — entirely in your browser.