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Math calculator

Kinetic Energy Calculator

Calculate kinetic energy, or solve backward for mass or velocity, with visible formula steps.

Kinetic energy125 J

This calculator uses kilograms, meters per second, joules, and foot-pounds. It assumes classical (non-relativistic) motion.

FormulaKE = ½ × m × v²
Calculation steps
  1. 5² = 25
  2. ½ × 10 × 25 = 125 J

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How it works

How to use this kinetic energy calculator

  1. Choose whether to solve for energy, mass, or velocity.
  2. Enter the two known values and the energy unit.
  3. Read the result and the substituted formula steps.

Formula

The calculation formula

Kinetic Energy = ½ × Mass × Velocity²
01

Square the object's velocity.

02

Multiply by mass.

03

Divide the product by two.

Worked examples

Example calculations

Find energy

A 10 kg object moving at 5 m/s has ½ × 10 × 5² = 125 joules of kinetic energy.

Find mass

If kinetic energy is 125 J and velocity is 5 m/s, mass is 2 × 125 ÷ 25 = 10 kg.

When to use it

Common use cases

  • Solve basic physics problems
  • Compare the effect of speed and mass
  • Estimate projectile or vehicle energy

Limits

Assumptions and limits

  • Uses SI base units: kilograms, meters per second, and joules.
  • Foot-pounds convert with 1 ft-lb = 1.3558179483 J.
  • The formula is classical and non-relativistic.

Questions

Frequently asked questions

Why does velocity have such a large effect?

Velocity is squared in the formula, so doubling velocity increases kinetic energy by a factor of four.

Can this calculator solve for mass or velocity?

Yes. Choose the value you want to find, then enter the other two known values.

Sources

Sources and review