Kilojoules (kJ) to Watt-hours (W·h) Conversion
Kilojoules
The kilojoule (kJ) is a unit of energy equal to exactly 1,000 joules. It is the standard unit for expressing food energy in most countries outside the United States, where food labels display energy in both kilojoules and kilocalories (kcal). One kilocalorie equals exactly 4.184 kilojoules. In thermodynamics and chemistry, reaction enthalpies and bond energies are commonly tabulated in kilojoules per mole (kJ/mol).
Watt-hours
The watt-hour (W·h) is a unit of energy equal to exactly 3,600 joules, defined as the energy consumed by a one-watt device operating for one hour. It is used in electrical engineering and consumer electronics for expressing battery capacities: a smartphone battery typically holds 10–20 Wh. In aviation, aircraft battery capacities are specified in watt-hours for international transport regulations (lithium batteries above 100 Wh face restrictions).
| Kilojoules (kJ) | Watt-hours (W·h) |
|---|---|
| 0.1 kJ | 0.027777777777778 W·h |
| 1 kJ | 0.27777777777778 W·h |
| 2 kJ | 0.55555555555556 W·h |
| 3 kJ | 0.83333333333333 W·h |
| 5 kJ | 1.3888888888889 W·h |
| 10 kJ | 2.7777777777778 W·h |
| 20 kJ | 5.5555555555556 W·h |
| 30 kJ | 8.3333333333333 W·h |
| 50 kJ | 13.888888888889 W·h |
| 100 kJ | 27.777777777778 W·h |
| 1000 kJ | 277.77777777778 W·h |
Frequently Asked Questions (FAQ)
How many watt-hours are in 1 kilojoules?
1 kilojoules (kJ) is exactly 0.277778 watt-hours (W·h).
How do I convert kilojoules to watt-hours?
Multiply the value in kilojoules by 0.277778 to get the result in watt-hours. Or use the converter above — type any number and see the result instantly.