Mass-Energy Calculator
Enter mass and the speed of light to compute energy via E = m·c² (rest energy).
Input Data
Results
At a glance:The mass-energy relation E = m·c² expresses that mass is a form of energy. The rest energy E of an object of mass m is m times c², where c is the speed of light. Because c² ≈ 9×10¹⁶ m²/s², even a small mass corresponds to a vast energy. In nuclear reactions a small mass defect (difference between reactant and product masses) is released as energy, which is the principle behind nuclear power and weapons.
Formula
Rest energy: E = m·c²
How to Use
- Enter the mass m (kg).
- Keep the default speed of light or adjust it.
- The calculator returns the equivalent rest energy E.
Case Studies
Energy of 1 g
m = 0.001 kg.
E = 0.001 × (2.998×10⁸)² ≈ 9×10¹³ J.
About 25 GWh, comparable to a small power plant's daily output.
FAQ
Why is the speed of light squared?
The constant c² is the conversion factor between mass and energy units. Its enormous value (≈9×10¹⁶) means a tiny mass equals a huge energy.
Where does mass-energy equivalence apply?
It applies universally, but is most visible in nuclear and particle physics where mass is converted to energy (fission, fusion, annihilation) and in cosmology.
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.