Work / Energy Calculator
Calculate mechanical work or energy from force and distance (W = Fd).
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500
About this calculator
What Are Work and Energy?
In physics, work is done when a force moves an object over a distance, and energy is the capacity to do work. They are measured in the same unit, the joule (J): one joule is the work done by a force of one newton over one meter. This work and energy calculator covers the core relationships — work from force and distance, kinetic energy from mass and speed, and potential energy from mass and height — so you can solve typical mechanics problems quickly.
Key Formulas
- Work: W = F × d × cos θ, where θ is the angle between the force and the direction of motion. For a force along the motion, W = F × d.
- Kinetic energy: KE = ½ m v² — the energy of motion. Doubling the speed quadruples the kinetic energy.
- Gravitational potential energy: PE = m g h — the energy stored by height. On Earth, g ≈ 9.81 m/s².
- Power: P = W ÷ t — the rate of doing work, measured in watts (1 W = 1 J/s).
The Work–Energy Theorem
The net work done on an object equals the change in its kinetic energy: Wnet = ΔKE. Push a shopping cart and it speeds up because your work becomes kinetic energy; friction does negative work and turns that energy into heat. This idea lets you solve many problems without tracking acceleration or time.
Conservation of Energy
Energy is never created or destroyed, only converted between forms. A ball dropped from a height loses potential energy and gains an equal amount of kinetic energy on the way down (ignoring air resistance). That conservation principle is what makes roller coasters, pendulums and hydroelectric dams predictable.
Everyday Units of Energy
Joules are small, so you will see kilojoules (kJ), calories, kilowatt-hours (kWh) and BTUs in daily life. One food Calorie is about 4,184 J, and one kilowatt-hour is 3.6 million joules. Use the Unit Conversion Calculator to move between them, and the Force Calculator to find the F in the work formula.
Worked example
A 50-newton force applied over 10 meters does 500 joules of work — half a kilojoule.
Frequently asked questions
What's the formula for work?
Work equals force times distance (W = Fd), assuming the force is applied in the same direction as the motion.
What's the difference between work and energy?
They're measured in the same units (joules) and are closely related — work is the process of transferring energy, often into kinetic or potential energy.
What if the force isn't in the same direction as the motion?
Only the component of force in the direction of motion does work — a force applied perpendicular to motion does zero work. This calculator assumes they're aligned.
What's a joule in everyday terms?
Lifting a 1 kg object about 10 cm against gravity takes roughly 1 joule of work.
