Kinetic Energy Calculator - KE = 0.5mv²
Calculate kinetic energy from mass and velocity, or solve for mass or velocity given the other two variables.
Result
9.0000
KE = 0.5 × m × v² = 0.5 × 2 × 3² = 9.0000 J
How to Calculate Kinetic Energy
Kinetic energy is the energy an object possesses due to its motion, equal to one-half its mass times the square of its velocity. This calculator solves for any one of the three variables — kinetic energy, mass, or velocity — given the other two, using standard SI units of kilograms, meters per second, and joules.
Example
A 2 kg object moving at 3 m/s has a kinetic energy of KE = 0.5 × 2 × 3² = 0.5 × 2 × 9 = 9 joules. If you instead knew the energy (9 J) and the mass (2 kg), you could solve for velocity: v = √(2 × 9 / 2) = 3 m/s.
Common Use Cases
- Physics homework covering the kinetic energy formula.
- Estimating the impact energy of a moving vehicle or projectile.
- Comparing how much energy is added by increasing speed versus mass.
FAQs
What units does this calculator use?
Standard SI units: mass in kilograms (kg), velocity in meters per second (m/s), and kinetic energy in joules (J), where 1 joule is the energy of a 1 kg object moving in a way that satisfies the formula above.
Does the direction of velocity matter?
No — kinetic energy depends on velocity squared, so only the object's speed (the magnitude of its velocity) matters, not its direction. A negative velocity value produces the same kinetic energy as the equivalent positive value.
Why does speed matter more than mass for kinetic energy?
Because kinetic energy scales with the square of velocity but only linearly with mass, doubling an object's speed quadruples its kinetic energy, while doubling its mass only doubles it — which is why speed has such an outsized effect on impact energy.