Gigajoule (GJ)

Metric (SI)Current unit

One billion joules, roughly the energy in 29 liters of petrol. Used for natural gas and district heating.

1 gigajoule = 1,000,000,000 joules (exactly).

About the gigajoule

One gigajoule is a billion joules, a size that only shows up when something large is being counted. An average lightning bolt carries about that much, and the superconducting magnet of the ATLAS experiment at CERN stores about 1.1 GJ of magnetic energy.

Everyday life can reach it too, just slowly. Filling a car with about 61 liters of gasoline, roughly 16 US gallons, puts in about 2 GJ of combustion energy. A standard refrigerator uses about 4.5 GJ in a year, and an average human heart muscle expends about 3.3 GJ over an 80-year lifetime.

Larger reference points sit nearby. One megawatt-hour is 3.6 GJ, exploding a ton of TNT releases about 4.2 GJ, and a barrel of oil equivalent is about 6.1 GJ. These comparisons explain why gigajoules suit annual household or building energy tallies better than joules or kilojoules.

Sources: Wikipedia: Orders of magnitude (energy); Wikipedia: Joule

Gigajoule conversion chart

1 gigajoule expressed in every other energy unit:

More Metric (SI) units

• joule (energy)
• kilojoule (energy)
• megajoule (energy)
• millijoule (energy)
• watt-hour (energy)
• kilowatt-hour (energy)
• megawatt-hour (energy)
• tonne of oil equivalent (energy)
• meter (length)
• kilometer (length)
• centimeter (length)
• millimeter (length)
• micrometer (length)
• nanometer (length)
• picometer (length)
• decimeter (length)

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