Kinetic Energy Calculator

This kinetic energy calculator uses the formula KE = ½mv² to find the energy of any moving object. Kinetic energy depends on both mass and the square of velocity — velocity is the dominant factor.

Step 1: Enter Mass and Velocity

Enter the object's mass (kg or lb) and its velocity (m/s or ft/s). Toggle the unit switch to change between metric and imperial mode.

Step 2: Click Calculate

The result shows kinetic energy in both Joules and BTU for easy comparison. The primary display uses the selected unit system.

Worked Examples

Car at highway speed: A 1,500 kg car at 27.8 m/s (100 km/h): KE = ½ × 1500 × 27.8² = 579,990 J ≈ 580 kJ. This is why high-speed crashes are so destructive.

Baseball pitch: A 0.145 kg baseball at 42 m/s (94 mph): KE = ½ × 0.145 × 42² = 127.9 J — about the same as a medium-size book falling from a table.

The Velocity-Squared Relationship

Doubling speed quadruples kinetic energy. A car at 60 mph has 4× the kinetic energy of the same car at 30 mph — this is why stopping distances increase dramatically at higher speeds.