Kinetic Energy Calculator
Calculate kinetic energy from mass and velocity using KE = 1/2 mv². Get instant results in joules for any moving object.
Examples
Running person (70 kg at 3 m/s)
KE = 0.5 × 70 × 3² = 315 J
- Mass
- 70 kg
- Velocity
- 3 m/s
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How It Works
Formula
Variables, symbols and units
- Kinetic energy(J)
- Mass(kg)
- Velocity(m/s)
Calculation method explained
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.
References and source material
Examples
Running person (70 kg at 3 m/s)70 kg · 3 m/s → 315 J
KE = 0.5 × 70 × 3² = 315 J
- Mass
- 70 kg
- Velocity
- 3 m/s
- Kinetic Energy
- 315 J
Moving car (1500 kg at 20 m/s)1,500 kg · 20 m/s → 300,000 J
KE = 0.5 × 1500 × 20² = 300,000 J
- Mass
- 1,500 kg
- Velocity
- 20 m/s
- Kinetic Energy
- 300,000 J
Tennis ball (0.058 kg at 50 m/s)0.058 kg · 50 m/s → 72.5 J
KE = 0.5 × 0.058 × 50² = 72.5 J
- Mass
- 0.058 kg
- Velocity
- 50 m/s
- Kinetic Energy
- 72.5 J