Find the rest energy E = m c² of a mass, in joules and gigajoules.
| Energy (J) | – |
| Energy (GJ) | – |
Use this calculator for Einstein’s rest-energy relation. The speed of light is c = 299792458 m/s. One gram (0.001 kg) is about 9.0×10¹³ J, tens of thousands of gigajoules. This is rest energy only, not the extra kinetic energy of a moving mass and not a reactor yield.
Mass must be greater than zero and already in kilograms. 1 g is 0.001 kg; 1 kg of rest mass is about 9.0×10¹⁶ J.
Mass (kg): Rest mass in kilograms.
Energy (J): Rest energy in joules.
Energy (GJ): The same energy in gigajoules (÷ 10⁹).
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