kJ to Wh Converter

How to convert kilojoules to watt-hours

FormulaWh = kJ × 0.2777777778

Because one watt-hour equals 3.6 kilojoules, you can also divide: Wh = kJ ÷ 3.6.

A kilojoule is smaller than a watt-hour: it takes 3.6 kilojoules to make one watt-hour.

Worked examples

1 kilojoule1 kJ × 0.2777777778 = 0.2777777778 Wh
5 kilojoules5 kJ × 0.2777777778 = 1.388888889 Wh
10 kilojoules10 kJ × 0.2777777778 = 2.777777778 Wh
20 kilojoules20 kJ × 0.2777777778 = 5.555555556 Wh
100 kilojoules100 kJ × 0.2777777778 = 27.77777778 Wh

Kilojoules to watt-hours conversion table

Values are calculated by the conversion engine and rounded to 8 significant figures.

Kilojoules to watt-hours: 0.1–10 kJ
Kilojoules (kJ)	Watt-hours (Wh)
0.1 kJ	0.027777778 Wh
0.25 kJ	0.069444444 Wh
0.5 kJ	0.13888889 Wh
1 kJ	0.27777778 Wh
2 kJ	0.55555556 Wh
3 kJ	0.83333333 Wh
4 kJ	1.1111111 Wh
5 kJ	1.3888889 Wh
6 kJ	1.6666667 Wh
7 kJ	1.9444444 Wh
8 kJ	2.2222222 Wh
9 kJ	2.5 Wh
10 kJ	2.7777778 Wh

Kilojoules to watt-hours: 12–1,000 kJ
Kilojoules (kJ)	Watt-hours (Wh)
12 kJ	3.3333333 Wh
15 kJ	4.1666667 Wh
20 kJ	5.5555556 Wh
25 kJ	6.9444444 Wh
30 kJ	8.3333333 Wh
40 kJ	11.111111 Wh
50 kJ	13.888889 Wh
75 kJ	20.833333 Wh
100 kJ	27.777778 Wh
250 kJ	69.444444 Wh
500 kJ	138.88889 Wh
1,000 kJ	277.77778 Wh

About the units

Kilojoule (kJ)

One thousand joules. Food labels in Australia and the EU list energy in kJ alongside kcal. One kilojoule equals 1,000 joules (J).

Watt-hour (Wh)

One watt sustained for an hour: 3,600 J. Battery capacities are rated in Wh.

Frequently asked questions

How many watt-hours are in one kilojoule?

There are 0.2777777778 watt-hours in one kilojoule, and this value is exact by definition.

How do I convert kilojoules to watt-hours?

Multiply the number of kilojoules by 0.2777777778. For example, 10 kJ × 0.2777777778 = 2.777777778 Wh.

How many kilojoules are in one watt-hour?

One watt-hour equals 3.6 kilojoules. That is the reverse factor, 1 ÷ 0.2777777778.

What is 10 kilojoules in watt-hours?

10 kJ = 2.777777778 Wh.

Is this kJ to Wh converter accurate?

Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.