Kinetic Energy Calculator

Calculate kinetic energy using KE = ½mv². Enter mass and velocity to find kinetic energy in joules.

Enter mass and velocity to calculate kinetic energy.

Kinetic Energy Formula

KE = ½ × m × v²

Where:

  • KE = kinetic energy (Joules, J)
  • m = mass (kg)
  • v = velocity (m/s)

Example

Problem: A 2 kg ball moves at 5 m/s. What is its kinetic energy?
Solution: KE = ½ × 2 × 5² = ½ × 2 × 25 = 25 J

Understanding Kinetic Energy

Kinetic energy is the energy an object possesses due to its motion. It increases with the square of velocity, meaning doubling the speed quadruples the kinetic energy.

This is why high-speed collisions are so much more destructive — a car traveling at 60 mph has four times the kinetic energy of one at 30 mph.

Common Unit Conversions

  • 1 Joule = 1 kg·m²/s²
  • 1 kJ = 1000 J
  • 1 calorie ≈ 4.184 J
  • 1 kWh = 3,600,000 J

FAQ

Why does velocity have a greater effect than mass?

Because velocity is squared in the formula, doubling velocity increases kinetic energy by 4×, while doubling mass only doubles it.

Can kinetic energy be negative?

No. Since velocity is squared and mass is always positive, kinetic energy is always zero or positive.

What is the relationship between kinetic energy and momentum?

KE = p²/(2m), where p is momentum. Objects with the same momentum can have different kinetic energies depending on their mass.

Last updated: 2026-08-08