A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix.
Gigajoules to Watt hours
Convert Gigajoule (GJ) to Watt-hour (Wh) instantly with an exact formula, conversion table, and FAQ.
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Convert gigajoules (GJ) to watt hours (Wh) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Wh = GJ × 277777.7778
Results update instantly for Gigajoules to Watt hours conversions.
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Formula
Wh = GJ × 277777.7778
GJ = Wh × 0.0000036
Conversion table
| 1 GJ | 277777.777778 Wh |
| 5 GJ | 1.388889e+06 Wh |
| 10 GJ | 2.777778e+06 Wh |
| 20 GJ | 5.555556e+06 Wh |
| 50 GJ | 1.388889e+07 Wh |
| 100 GJ | 2.777778e+07 Wh |
| 500 GJ | 1.388889e+08 Wh |
| 1000 GJ | 2.777778e+08 Wh |
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How the formula works
Both gigajoule and watt-hour measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in gigajoules by 277777.7778 to get watt hours. To reverse the conversion, multiply a watt-hour value by 0.0000036 to get back to gigajoules.
Frequently asked questions
What is Gigajoule (GJ)?
A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix.
What is Watt-hour (Wh)?
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
How do I convert gigajoules to watt hours?
Multiply the gigajoule value by 277777.7778 to get the equivalent in watt hours. For example, 5 GJ × 277777.7778 = 1.388889e+06 Wh.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 277777.7778 is an exact, non-rounded value.
Can I convert watt hours back to gigajoules?
Yes. Divide the watt-hour value by 277777.7778, or multiply it by 0.0000036, to get gigajoules.
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About converting gigajoules to watt hours
A gigajoule (GJ) is a metric-prefixed unit of energy equal to 109 joules, using the SI giga prefix. A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Use this calculator to move between gigajoules and watt hours accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.