How to convert watt-hours to kilojoules
To convert a measurement in watt-hours to kilojoules, multiply the value by 3.6. The conversion factor comes from the relationship between both units and the joule.
For example, to convert 5 Wh to kilojoules: 5 × 3.6 = 18 kJ.
What is a watt-hour?
A watt-hour is the energy delivered by one watt of power over one hour, equal to 3,600 joules. The watt-hour emerged with the electrical industry as a practical measure of energy use over time. It underpins the kilowatt-hour that appears on electricity bills worldwide.
Common uses of watt-hours include: Battery capacity ratings; Small electronics energy use; Solar panel and storage sizing; Portable power station specifications.
What is a kilojoule?
A kilojoule equals 1,000 joules and is the standard metric unit for expressing food energy on nutrition labels in most of the world. As metric countries adopted SI units for food labeling, the kilojoule replaced the food calorie on packaging in regions such as Australia, New Zealand, and the European Union (shown alongside kcal).
Common uses of kilojoules include: Food energy on nutrition labels; Dietary and exercise energy tracking; Chemical reaction energy (enthalpy); Battery and mechanical energy specs.
Watt-hours to kilojoules worked examples
Here are some common values converted:
1 Wh = 3.6 kJ 5 Wh = 18 kJ 10 Wh = 36 kJ 50 Wh = 180 kJ 100 Wh = 360 kJ
Frequently asked questions
How many kilojoules are in one watt-hour?
One watt-hour (Wh) equals 3.6 kilojoules (kJ). Multiply any value in watt-hours by 3.6 to convert to kilojoules.
How do I convert watt-hours to kilojoules?
Multiply the value in watt-hours by 3.6. For example, 5 Wh × 3.6 = 18 kJ.
How do I convert kilojoules to watt-hours?
Multiply the value in kilojoules by 0.277777777778, or divide by 3.6. Use the swap button on the converter above to reverse the direction.
Is the watt-hour to kilojoule conversion exact?
The thermochemical calorie is defined as exactly 4.184 J and the BTU as 1055.056 J. Conversions between SI energy units are exact.
What is the formula for watt-hours to kilojoules?
The formula is: kJ = Wh × 3.6. This comes from the definition of both units relative to the joule.