Kinetic Energy Calculator
Calculate the kinetic energy of a moving object from its mass and velocity.
How it works
KE = ½ · m · v²
Kinetic energy is the energy an object has because it is moving. It scales with the square of velocity, so doubling the speed quadruples the energy — which is why impact energy rises so fast with speed.
Worked example
A 10 kg object at 20 m/s has KE = ½ × 10 × 20² = 2,000 J (2 kJ).
Frequently asked questions
Why does velocity matter more than mass?
Kinetic energy is proportional to velocity squared but only linearly to mass, so speed has a far larger effect. Doubling speed quadruples the energy; doubling mass only doubles it.
What units are used?
With mass in kilograms and velocity in metres per second, the result is in joules (J), the SI unit of energy.
Is this the same as momentum?
No. Momentum is m·v (a vector), while kinetic energy is ½·m·v² (a scalar). They describe different aspects of motion.
Related calculators
Educational estimate. Check the formula and units for your exact case.