Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity using KE = 1/2 mv². Get instant results in joules for any moving object.
kg
m/s
Examples
KE = 0.5 × 70 × 3² = 315 J
Kinetic Energy
315 J
Moderate energy — comparable to a thrown ball or a person jogging.
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Examples
How It Works
Formula
Variables
- Kinetic energy(J)
- Mass(kg)
- Velocity(m/s)
Enter the mass of the object in kilograms and its velocity in metres per second. The calculator applies KE = 1/2 mv² to return the kinetic energy in joules.
Kinetic energy follows from the work-energy theorem: the net work done to accelerate an object from rest to velocity v equals 1/2 mv². The calculator squares your velocity, multiplies by the mass, and halves the product. Because v is squared, doubling speed quadruples energy — that is why crash energy scales sharply with vehicle speed.
Frequently Asked Questions
01What is kinetic energy?
Kinetic energy is the energy an object possesses due to its motion. It depends on both the mass and the square of the velocity: KE = 1/2 mv².
02What units does kinetic energy use?
Kinetic energy is measured in joules (J) when mass is in kilograms (kg) and velocity is in metres per second (m/s). 1 J = 1 kg·m²/s².
03Why is velocity squared in the formula?
Velocity is squared because kinetic energy is derived from the work-energy theorem. Doubling the speed quadruples the energy, so impact energy rises sharply with speed.
04Can kinetic energy be negative?
No. Mass is always positive and velocity is squared, so kinetic energy is always zero or positive. An object at rest has zero kinetic energy.
05What is the difference between kinetic and potential energy?
Kinetic energy is the energy of motion (KE = 1/2 mv²), while potential energy is stored energy due to position or configuration (e.g., gravitational PE = mgh). Together they form mechanical energy.