Work Calculator

Calculate work done by a constant force over a distance, including the effect of the angle between force and displacement.

Mechanical work
Enter force, displacement, and their included angle. Use zero degrees when force acts directly along the motion.

About calculating mechanical work

Mechanical work describes energy transferred by a force while its point of application moves. For a constant force and straight displacement, the scalar work is W = Fd cos(θ). Here F is force magnitude in newtons, d is displacement magnitude in metres, and θ is the angle between the force and displacement vectors. Multiplying newtons by metres produces joules, the SI unit of both work and energy. The cosine factor selects the component of force acting along the direction of motion. At zero degrees, force and displacement point together, cosine is one, and all of the force performs positive work. At 90 degrees, the force is perpendicular to motion and performs zero work. A familiar example is uniform circular motion: the inward centripetal force is perpendicular to instantaneous motion, so it changes direction but not speed. At angles greater than 90 degrees and less than 270 degrees, cosine is negative and the force removes mechanical energy from the object. Negative work does not mean that no physical interaction occurred. It means the force component opposes displacement. Friction on a sliding object commonly performs negative work, while an applied pulling force may perform positive work. The net work from all forces equals the change in kinetic energy, a relationship known as the work-energy theorem. Calculating each force separately and summing its signed work can therefore predict how an object's speed changes. This calculator assumes a constant force, constant angle, and a single straight displacement. If force varies with position, work is the integral of the force component along the path. Springs, changing fluid resistance, and variable engine thrust need that more general treatment. A curved path may also require dividing motion into small segments when the force direction changes relative to displacement. Use magnitudes in newtons and metres, and specify the included angle in degrees. The result gives work in joules and also reports the force component parallel to motion. Distinguish displacement from total path length: only the displacement occurring while the stated force and angle apply belongs in this formula. The calculator is useful for mechanics exercises and estimates, but complex systems may also involve rotational work, deformation, heat, and losses.

Work calculation examples

InputsCalculated outputInterpretation
50 N, 10 m, 0°500 JForce acts directly along motion
100 N, 5 m, 60°250 JOnly half the force acts along motion
200 N, 3 m, 90°0 JPerpendicular force performs no work
40 N, 8 m, 180°−320 JForce directly opposes motion

How to use the calculator

  1. Enter the constant force magnitude in newtons.
  2. Enter the displacement over which that force acts in metres.
  3. Enter the angle between force and displacement in degrees.
  4. Select Calculate Work and interpret the sign of the result.

Frequently asked questions

When is work positive?

Work is positive when the force has a component in the direction of displacement. It transfers energy to the moving object or system.

Can mechanical work be negative?

Yes. Work is negative when a force component opposes displacement, as friction often does to a sliding object.

Why does a perpendicular force do no work?

A perpendicular force has no component along displacement, so their dot product is zero. It can still change the direction of velocity without changing kinetic energy.

What angle should I enter for a parallel force?

Enter zero degrees when force and motion point in the same direction. Enter 180 degrees when they point in exactly opposite directions.

Does this formula apply to a changing force?

Not directly, because this calculator assumes force and angle stay constant. A changing force requires integrating its component over the path.