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Science 2026-05-04 3 min read By Konvertibly Team

Kinetic Energy Calculator: Mass, Velocity, and KE Formula

Calculate kinetic energy from mass and velocity using KE = ½mv². Covers units, worked examples for vehicles and projectiles, and the relationship between speed and energy.

Kinetic Energy Calculator: Mass, Velocity, and KE Formula

Kinetic Energy Formula

Kinetic energy is the energy an object possesses due to its motion. It depends on both mass and the square of velocity — doubling speed quadruples kinetic energy.

Formula

KE = ½ × m × v²
m = mass (kg)
v = velocity (m/s)
KE = Joules (J)

Worked Examples

Car: m=1500 kg, v=30 m/s (108 km/h)
KE = 0.5 × 1500 × 900 = 675,000 J = 675 kJ

Tennis ball: m=0.057 kg, v=70 m/s (252 km/h serve)
KE = 0.5 × 0.057 × 4900 = 139.7 J

Bullet: m=0.009 kg, v=900 m/s
KE = 0.5 × 0.009 × 810,000 = 3,645 J

Why Speed Matters More Than Mass

Doubling mass:   KE × 2
Doubling speed:  KE × 4 (squared relationship)

Car at 60 mph vs 120 mph:
4× the KE → 4× longer stopping distance
(not 2× — this surprises most drivers)

Unit Conversions

  • 1 J = 1 kg·m²/s²
  • 1 kJ = 1000 J
  • 1 kWh = 3,600,000 J
  • 1 BTU = 1055 J

Calculate kinetic energy: Free Kinetic Energy Calculator