Kinetic Energy Calculator

Calculate kinetic energy, mass, or velocity using KE = ½mv²

Calculate

Choose what to calculate

Input Values

Enter known values

Mass of the moving object

Speed of the object

Common Examples

Car (1000 kg at 20 m/s)
m = 1000 kg, v = 20 m/s → KE = 200,000 J
≈ 72 km/h
Baseball (0.145 kg at 40 m/s)
m = 0.145 kg, v = 40 m/s → KE = 116 J
Fast pitch
Bullet (0.01 kg at 400 m/s)
m = 0.01 kg, v = 400 m/s → KE = 800 J
High velocity
Runner (70 kg at 8 m/s)
m = 70 kg, v = 8 m/s → KE = 2,240 J
Sprint speed

Unit Conversions

Velocity: 1 m/s = 3.6 km/h = 2.237 mph
Energy: 1 J = 0.239 cal = 0.000278 Wh
Mass: 1 kg = 1000 g = 2.205 lb

Result

Calculated kinetic energy

125
Joules (J)
= 0.13 kJ
= 29.88 calories
= 0.034750 Wh

Kinetic Energy Formula

KE = ½mv²
Kinetic Energy = ½ × Mass × Velocity²
KE = Kinetic Energy (Joules)
m = Mass (kilograms)
v = Velocity (meters per second)
Calculating: KE = ½ × 10 kg × (5 m/s)² = 125 J
Alternative Forms:
• m = 2KE / v²
• v = √(2KE / m)

Key Concepts

Energy of Motion:
Kinetic energy is the energy an object possesses due to its motion
Velocity Squared:
Doubling velocity quadruples kinetic energy (v² relationship)
Scalar Quantity:
KE is always positive and has no direction
Work-Energy Theorem:
Work done on an object equals its change in kinetic energy

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About Kinetic Energy Calculator

Kinetic Energy Equation

This calculator uses the kinetic energy equation KE = ½mv², which calculates the energy an object has due to its motion. This fundamental equation in classical mechanics shows that kinetic energy is proportional to mass and the square of velocity.

Features

  • Calculate kinetic energy from mass and velocity
  • Calculate mass from kinetic energy and velocity
  • Calculate velocity from kinetic energy and mass
  • Quick velocity presets (walking, running, cycling, car)
  • Automatic unit conversions (J, kJ, MJ, cal, Wh)
  • Real-world examples from everyday objects
  • Velocity conversions (m/s, km/h, mph)

Understanding Kinetic Energy

Kinetic energy is one of the two main forms of mechanical energy (along with potential energy). The v² term means that velocity has a much greater effect on kinetic energy than mass - doubling the velocity quadruples the energy, while doubling the mass only doubles it. This is why high-speed collisions are so much more dangerous than low-speed ones.

Applications

  • Vehicle safety and crash analysis
  • Sports physics and ballistics
  • Energy efficiency calculations
  • Collision and impact studies
  • Mechanical engineering design
  • Renewable energy (wind, hydro)
  • Particle physics and accelerators
  • Aerospace and rocket science

Important Notes

  • This formula applies to non-relativistic speeds (v << c)
  • Kinetic energy is frame-dependent (depends on observer)
  • Total mechanical energy = KE + PE (potential energy)
  • Energy is conserved in isolated systems
  • 1 Joule = 1 kg⋅m²/s²
  • Rotational kinetic energy uses a different formula