Kinetic Energy Calculator
Calculate kinetic energy with KE = ½mv². Solve for kinetic energy, mass, or velocity in SI units (joules, kg, m/s) by entering the other two.
Kinetic energy (KE = ½mv²)
9 J
Kinetic energy: KE = ½ m v². Energy in joules (J), mass in kg, velocity in m/s.
Frequently Asked Questions
What is the kinetic energy formula?
Kinetic energy is KE = ½ × m × v², where m is mass in kilograms and v is speed in metres per second. The result is in joules (J).
How do I calculate kinetic energy?
Square the velocity, multiply by the mass, then halve it. For example, a 2 kg object moving at 3 m/s has KE = ½ × 2 × 3² = 9 joules.
How do I find velocity from kinetic energy?
Rearrange the formula to v = √(2·KE / m). Double the energy, divide by the mass, and take the square root. The velocity is always positive in magnitude.
How do I find mass from kinetic energy?
Rearrange to m = 2·KE / v². Double the energy and divide by the velocity squared.
Why does kinetic energy depend on the square of velocity?
Because doubling the speed quadruples the kinetic energy. This is why stopping distances and collision energy rise so sharply with speed — energy scales with v², not v.