Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity.
Result
The Kinetic Energy Formula
Kinetic energy is the energy an object possesses due to its motion. In SI units it is measured in joules (J) and given by:
KE = ½ · m · v²
- KE - Kinetic energy (joules, J)
- m - Mass (kilograms, kg)
- v - Velocity (meters per second, m/s)
Rearranging the formula lets you solve for mass (m = 2·KE / v²) or velocity (v = √(2·KE / m)).
Why Kinetic Energy Scales with v²
Because velocity is squared in the formula, kinetic energy grows much faster than speed. Doubling an object's speed does not double its kinetic energy - it quadruples it (2² = 4). Tripling the speed multiplies the energy by nine (3² = 9).
This is why stopping distances and collision damage rise so sharply with speed: a car traveling at 60 km/h carries four times the kinetic energy it had at 30 km/h, even though its mass is unchanged.
The Work-Energy Theorem
The work-energy theorem states that the net work done on an object equals its change in kinetic energy:
Wnet = ΔKE = KEfinal − KEinitial
In other words, applying a net force over a distance changes an object's speed, and the energy transferred is exactly the change in its kinetic energy. This links the concepts of force, work, and motion.