Convert Mass and Energy

A calculator for the energy generated by the conversion of a percentage of mass. Theoretically, mass can be converted into energy according to the famous formula from Albert Einstein's theory of special relativity, E=mc². Since c, the speed of light, is a very high value, its square is an enormous number. Consequently, a gigantic amount of energy could be produced from a small quantity of mass. Practically, this is not that simple to do. In a chemical reaction, even the most violent one, only a tiny, barely measurable fraction of the mass is converted into energy. During the nuclear fusion of hydrogen into helium within stars, the figure is approximately 0.71 percent. This allows our Sun to shine brightly for billions of years while experiencing only a moderate loss of mass.

Mass to Energy

Mass:		μg, 10^-9mg, 10^-6g, 10^-3kgt, 10^3kt, 10^6Mt, 10^9Gt, 10^12
Mass conversion:		%
Energy:		mJ, 10^-3JkJ, 10^3MJ, 10^6GJ, 10^9TJ, 10^12PJ, 10^15EJ, 10^18ZJ, 10^21YJ, 10^24

Round to   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15   decimal places.

Example: One kilogram of H₂ converted into He, resulting in a mass loss of 0.71 percent, generates 629 terajoules of energy. This corresponds to a TNT equivalent of 150 kilotons (150,000 tons).

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Mass to Power

Mass:		μg, 10^-9mg, 10^-6g, 10^-3kgt, 10^3kt, 10^6Mt, 10^9Gt, 10^12
Mass conversion:		%
Time:		ps, 10^-12ns, 10^-9µs, 10^-6ms, 10^-3sminhda
Power:		nW, 10^-9μW, 10^-6mW, 10^-3WkW, 10^3MW, 10^6GW, 10^9TW, 10^12PW, 10^15EW, 10^18ZW, 10^21YW, 10^24

Round to   0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15   decimal places.

To fuse the one kilogram of hydrogen from the example above, the Sun takes approximately 1.667 picoseconds (10^-12). This gives the Sun a power output of about 383 yottawatts.

A loss of solar matter amounting to one kilogram every 1.667 picoseconds appears high. In reality, however, over the course of its approximately 10-billion-year lifespan as a main-sequence star, the Sun will convert only about 0.03 percent of its total mass into radiant energy. Mass loss in nuclear fission is significantly lower than in nuclear fusion, around 0.1 percent for uranium-235. Conversion rates of nearly 100 percent occur during the annihilation of matter and antimatter. The reverse process, the creation of matter and antimatter from energy, is also physically possible under very specific conditions.

Last updated on 06/28/2026. Author: Jürgen Kummer

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