Physics

Work Calculator

Work out physical work from force, distance and angle — W = Fd cos(θ) — including why a sideways push can do zero work at all.


Work Calculator

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In physics, “work” has a precise meaning that does not always match the everyday sense of effort. This calculates it from force, distance and the angle between them.

How it works

Work done

W = F d cos(θ)

F is force in newtons, d is distance moved in metres, θ is the angle between the force and the direction of motion. W comes out in joules.

Why the angle changes everything

Only the component of a force that acts along the direction of motion does any work. Push a box forward and every newton of that push counts toward the work done. Carry a box at a constant height while walking forward, and the force holding it up is entirely perpendicular to your forward motion — at exactly 90°, cos(90°) is zero, so this definition says zero work is done, however tiring the carrying actually is. That gap between the physics definition and the everyday sense of effort is the single most common confusion this calculator exists to clear up.

How to use this calculator

  1. Enter the force in newtons.
  2. Enter the distance moved in metres.
  3. Enter the angle between the force and the direction of motion — 0° if they are fully aligned.

Frequently asked questions

Why can work come out negative?

When the angle is past 90°, the force opposes the motion rather than assisting it — friction slowing a sliding object is a classic example. Negative work means energy is being removed from the moving object, not added to it.

If I hold something heavy but don’t move, is that zero work?

By this definition, yes — no distance moved means no work done, regardless of how much force or effort is involved. This is exactly the everyday-versus-physics gap: holding a weight is tiring, but the formula requires movement for any work to register.

How does work relate to energy?

Work done on an object equals the energy transferred to or from it — this is why work and energy share the same unit, the joule. Lifting an object does work against gravity equal to the potential energy it gains.

Why does carrying something at constant height do zero work by this definition?

Because the force holding it up (against gravity) is vertical, while the motion (walking forward) is horizontal — perpendicular directions, so cos(90°) = 0. The muscular effort is real, but no work is done on the object in the physics sense, since its height, and therefore its potential energy, is not changing.

Does the object need to move in a straight line for this formula to apply?

This version assumes a constant force over a straight-line distance at a fixed angle. Work along a curved path or with a changing force needs the more general calculus definition, which this calculator does not cover.

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Written by

R. Solano

Physics writer

R. Solano writes the physics calculators, spanning mechanics, electricity, optics and thermodynamics. Each page names the physical model it uses and the conditions under which that model holds — ideal gas, no air resistance, small-angle approximation — because a physics result without its assumptions is a number without a meaning. Formulas are given in symbols first, then in the calculator.

Reviewed by

V. Kowalski

Calculator reviewer — physics and engineering

V. Kowalski reviews the physics and engineering calculators, checking that each page states the physical model it assumes and that the stated model matches the formula actually implemented. Review covers unit consistency throughout a calculation and whether approximations are flagged where the underlying physics is more complicated than the formula suggests.

How we write and review

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