Science · Physics / Mechanics

Kinetic Energy Calculator

Work out the energy of any moving object. Give mass and velocity to find KE, or pick energy as the input and solve for mass or speed instead.

Solve for:

KE · energy

m · mass

v · velocity

Solved value

KE—

Kinetic energy

KE = ½mv²

Energy in joules is half the mass (kg) times the velocity (m/s) squared. Because velocity is squared, doubling the speed quadruples the energy — a car at 100 km/h has four times the kinetic energy of the same car at 50 km/h. Rearranged: m = 2KE/v² and v = √(2KE/m).

🔢 Three-way solver

Solve for energy, mass or velocity — pick the unknown.

🔩 Unit aware

J / kJ / cal / kcal, kg / g / lb and m/s / km/h / mph all convert.

📈 Worked steps

See the formula rearranged with every number substituted.

🚜 Real-world feel

1 kg at 20 m/s holds 200 J — about the energy of a baseball pitch.

More mechanics & energy

Potential energy is the other half of the same story.

Potential Energy Calculator