Gigajoule is 1000000000 joule units.
Gigajoules to Watt-hours Converter — GJ to Wh
Convert Gigajoule (GJ) to Watt-hour (Wh) using the exact conversion factor (1 gigajoule = 277,777.7778 watt-hour). See the formula, worked examples, conversion table, and common uses.
Gigajoules to Watt-hours converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour is 3,600 joules.
Result = input x 1e+9 / 3600.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Gigajoules to Watt-hours
Gigajoule and Watt-hour both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Specifically: Gigajoule is 1000000000 joule units, and a watt-hour is 3,600 joules.
Formula
watt-hours = gigajoules × 277777.777778
This factor comes from each unit's defined relationship to the category's base unit: 1 gigajoule equals 1000000000 base units, and 1 watt-hour equals 3600 base units, so dividing one by the other gives the direct gigajoule-to-watt-hour factor of 277777.777778.
Simple example
1 GJ × 277777.7778 = 277,777.7778 Wh
1 gigajoule = 277,777.7778 watt-hours.
Real-world example
100 GJ × 277777.7778 = 27,777,777.78 Wh
100 gigajoules = 27,777,777.78 watt-hours.
Conversion table
| Gigajoule (GJ) | Watt-hour (Wh) |
|---|---|
| 1 GJ | 277,777.7778 Wh |
| 10 GJ | 2,777,777.778 Wh |
| 100 GJ | 27,777,777.78 Wh |
| 500 GJ | 138,888,888.9 Wh |
| 1,000 GJ | 277,777,777.8 Wh |
| 2,000 GJ | 555,555,555.6 Wh |
Reverse conversion: Watt-hour to Gigajoule
1 Wh × 0.0000036 = 0.0000036 GJ
1 watt-hour = 0.0000036 gigajoules.
gigajoules = watt-hours × 0.0000036
For a page dedicated to this direction, see Watt-hour to Gigajoule.
Understanding the Gigajoule (GJ)
Gigajoule is 1000000000 joule units.
Understanding the Watt-hour
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Where it's used: Universal — standard consumer-electronics and battery energy unit worldwide
Wh vs. kWh. The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.
Uses of the Watt-hour today
- Phone, laptop, and power-bank battery capacity ratings
- Electric-vehicle battery capacity specifications
- Small-scale renewable energy (solar panel) output ratings
Watt-hour — sources
- BIPM SI Brochure — Watt-hour as a common energy unit derived from the coherent SI units watt and second (via the hour).
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many watt-hours are in 1 gigajoule?
1 gigajoule equals 277,777.7778 watt-hours, using the exact defined conversion factor rather than an estimate.
How do I convert gigajoule to watt-hour?
Multiply the gigajoule value by 277777.7778. The converter above does this instantly to whatever precision you set.
How do I convert watt-hour back to gigajoule?
Use the reverse factor: 1 watt-hour equals 0.0000036 gigajoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a gigajoule?
Gigajoule (GJ) is a unit of energy.
What is a watt-hour?
Watt-hour (Wh) measures energy. The energy delivered by one watt of power sustained for one hour — equal to 3,600 joules. It is classified as a metric derived energy unit.
Is the gigajoule to watt-hour conversion exact?
Yes. Both gigajoule and watt-hour are defined by fixed standards rather than physical artifacts, so the factor of 277777.7778 used above is exact to as many digits as you choose to display.
What is the difference between wh vs. kwh?
The same unit at different scales: 1,000 Wh equals 1 kWh. Wh suits small consumer-electronics batteries; kWh is used for household electricity billing and larger energy storage.