Watt-hour to Kilojoule (Wh to kJ) Converter
1 watt-hour equals 3.6 kilojoules (kJ) exactly — multiply watt-hours by 3.6 to convert. The factor is exact because one watt-hour is 3,600 joules, which is 3.6 kilojoules.
The formula
To convert watt-hours to kilojoules, multiply by 3.6:
kJ = Wh × 3.6
For example, 10 Wh × 3.6 = 36 kJ. To reverse it, divide by 3.6 (or multiply by 0.27777778).
Conversion table
| Watt-hours (Wh) | Kilojoules (kJ) |
|---|---|
| 1 | 3.6 |
| 2 | 7.2 |
| 3 | 10.8 |
| 5 | 18 |
| 10 | 36 |
| 25 | 90 |
| 50 | 180 |
| 100 | 360 |
| 500 | 1800 |
| 1000 | 3600 |
How to convert online
- Type the number of watt-hours into the first box.
- Read the kilojoule result instantly in the second box.
- Or enter a kilojoule value to convert back to watt-hours.
Use the Watt-hour to Kilojoule Converter — free and instant in your browser.
Where this conversion is used
Watt-hours to kilojoules is a common bridge between the practical energy unit shown on batteries and appliances and the SI joule used in physics and engineering. It appears in electronics, thermodynamics homework, and energy-storage specs where kJ is the standard.
FAQ
How many kilojoules are in a watt-hour?
One watt-hour equals 3.6 kilojoules. So 10 Wh is 36 kJ and 100 Wh is 360 kJ.
What is the formula to convert watt-hours to kilojoules?
Multiply the watt-hour value by 3.6: kJ = Wh × 3.6. The converter applies this exact factor automatically.
How do I convert kilojoules back to watt-hours?
Divide by 3.6, or multiply by 0.27777778. For instance, 36 kJ ÷ 3.6 = 10 Wh.
Is the conversion exact?
Yes. Since 1 Wh is exactly 3,600 J = 3.6 kJ, the conversion is exact with no rounding.
Related converters
- Kilojoule to Watt-hour Converter
- Watt-hour to Joule Converter
- Watt-hour to Calorie Converter
- Watt-hour to Kilocalorie Converter
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Recommended reading
Watt-hour to Kilowatt-hour (Wh to kWh) Converter
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