Mass-Energy Equivalence (E=mc²)

Calculate the energy contained within a specific mass using Einstein's famous equation.

Mass Input

Mass (m) (kg)

Energy Results

Enter mass in kilograms

About this calculator

Quick Reference

mMass in kilograms

c299,792,458 m/s

EEnergy in Joules

c²≈ 8.987 × 10¹⁶ m²/s²

Overview

In physics, mass–energy equivalence is the principle that anything having mass has an equivalent amount of energy and vice versa.

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Pro Tips

Formula: E = m * c².
The constant c is the speed of light in a vacuum (approx 3 × 10⁸ m/s).
Because c² is a very large number, a small amount of mass corresponds to a huge amount of energy.

Fun Facts

"If you could convert just 1 gram of mass entirely into energy, it would be equivalent to' the energy of about 21.5 kilotons of TNT."
"Nuclear power plants work by converting a small fraction of the mass of uranium into heat energy."
"This equation also implies that as an object's energy increases (e.g., by moving faster), its relativistic mass also increases."

Formula: E = mc²