Kinetic energy calculator
Calculate the kinetic energy of a body from its mass and speed.
Use speed in m/s (divide km/h by 3.6).
How the calculation works
Kinetic energy is the energy of motion: KE = ½ · m · v², with mass in kg and speed in m/s. The result is in joules (J).
Examples
- A 2 kg ball at 10 m/s: ½ × 2 × 10² = 100 J.
- A 1,000 kg car at 100 km/h (~27.8 m/s): ~386 kJ.
Frequently asked questions
Why is speed squared?
It is the nature of the formula (½mv²). That's why doubling speed quadruples the energy — and a crash's impact.
Relation to potential energy?
In a fall, potential energy (mgh) becomes kinetic. At the ground, ½mv² = mgh, giving impact speed v = √(2gh).
Can kinetic energy be negative?
No. Since mass and v² are always positive, kinetic energy is always ≥ 0.
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Updated on June 18, 2026 · by Rafael Rossi · Methodology & sources