Convert Kilojoules to Watt-hours
1 kilojoule (kJ) equals 0.2777777778 watt-hours (Wh).
1 kJ = 0.2777777778 Wh
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk kilojoule to watt-hour converter to paste a column from Excel.
How to Convert Kilojoule to Watt-hour
- 1 kJ = 0.2777777778 Wh
- 1 Wh = 3.6 kJ
- Example: convert 15 kJ to Wh: 15 kJ = 15 × 0.2777777778 Wh = 4.166666667 Wh
Formula
Wh = kJ × 0.2777777777778
or Wh = kJ ÷ 3.6
Derivation from SI units:
- 1 kJ = 10³ J
- 1 Wh = 1 W × 3600 s = 3600 J
- 1 kJ = 1000 J ÷ 3600 J per Wh = 0.2777777777778 Wh
Both units are defined exactly, so the factor is exact. Kilojoule definition: kilojoule; Watt-hour definition: watt-hour.
Worked examples
- A reading of 100 kJ converts to 27.77777778 Wh.
100 kJ × 0.2777777778 = 27.77777778 Wh - A value of 1000 kJ is 277.7777778 Wh.
1000 kJ × 0.2777777778 = 277.7777778 Wh
Kilojoule to Watt-hour conversion table
| Kilojoules (kJ) | Watt-hours (Wh) |
|---|---|
| 1 kJ | 0.2777777778 Wh |
| 4.184 kJ | 1.162222222 Wh |
| 10 kJ | 2.777777778 Wh |
| 50 kJ | 13.88888889 Wh |
| 100 kJ | 27.77777778 Wh |
| 250 kJ | 69.44444444 Wh |
| 500 kJ | 138.8888889 Wh |
| 840 kJ | 233.3333333 Wh |
| 1000 kJ | 277.7777778 Wh |
| 2000 kJ | 555.5555556 Wh |
| 8700 kJ | 2416.666667 Wh |
| 10000 kJ | 2777.777778 Wh |
Where it's used
Kilojoules are used for nutrition labels (kJ per serving), while watt-hours appear in battery capacity (phone ≈ 15 Wh; airline limit 100 Wh per power bank). Both measure energy, work and heat, so the conversion is a fixed factor.
Kilojoule to other energy units
| Conversion | 1 kJ equals |
|---|---|
| kilojoule to joule | 1000 J |
| kilojoule to megajoule | 0.001 MJ |
| kilojoule to calorie | 239.0057361 cal |
| kilojoule to kilocalorie | 0.2390057361 kcal |
| kilojoule to watt-hour | 0.2777777778 Wh |
| kilojoule to kilowatt-hour | 0.0002777777778 kWh |
| kilojoule to BTU | 0.9478171203 BTU |
| kilojoule to therm | 0.00000948043428 thm |
| kilojoule to electronvolt | 6.241509074 × 10²¹ eV |
| kilojoule to foot-pound | 737.5621493 ft·lbf |
| kilojoule to erg | 10000000000 erg |
Frequently asked questions
How many watt-hours are in 1 kilojoule?
1 kJ = 0.2777777778 Wh.
How do I convert kilojoules to watt-hours?
Multiply the value in kJ by 0.2777777778, or divide it by 3.6. For example, 15 kJ × 0.2777777778 = 4.166666667 Wh.
Is the kJ to Wh conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "watt hour (W·h)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Kilojoules to Watt-hours. Retrieved October 17, 2026, from https://scientificconverters.com/energy/kilojoules-to-watt-hours/
IEEE
Scientific Converters, "Convert Kilojoules to Watt-hours," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/kilojoules-to-watt-hours/