Wh to kJ Converter

How to convert watt-hours to kilojoules

FormulakJ = Wh × 3.6

Multiply the value in watt-hours by 3.6. To go the other way, multiply by 0.2777777778 (or divide by 3.6).

A watt-hour is larger than a kilojoule: one watt-hour contains 3.6 kilojoules.

Worked examples

1 watt-hour1 Wh × 3.6 = 3.6 kJ
5 watt-hours5 Wh × 3.6 = 18 kJ
10 watt-hours10 Wh × 3.6 = 36 kJ
20 watt-hours20 Wh × 3.6 = 72 kJ
100 watt-hours100 Wh × 3.6 = 360 kJ

Watt-hours to kilojoules conversion table

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

Watt-hours to kilojoules: 0.1–10 Wh
Watt-hours (Wh)	Kilojoules (kJ)
0.1 Wh	0.36 kJ
0.25 Wh	0.9 kJ
0.5 Wh	1.8 kJ
1 Wh	3.6 kJ
2 Wh	7.2 kJ
3 Wh	10.8 kJ
4 Wh	14.4 kJ
5 Wh	18 kJ
6 Wh	21.6 kJ
7 Wh	25.2 kJ
8 Wh	28.8 kJ
9 Wh	32.4 kJ
10 Wh	36 kJ

Watt-hours to kilojoules: 12–1,000 Wh
Watt-hours (Wh)	Kilojoules (kJ)
12 Wh	43.2 kJ
15 Wh	54 kJ
20 Wh	72 kJ
25 Wh	90 kJ
30 Wh	108 kJ
40 Wh	144 kJ
50 Wh	180 kJ
75 Wh	270 kJ
100 Wh	360 kJ
250 Wh	900 kJ
500 Wh	1,800 kJ
1,000 Wh	3,600 kJ

About the units

Watt-hour (Wh)

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

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).

Frequently asked questions

How many kilojoules are in one watt-hour?

There are 3.6 kilojoules in one watt-hour, and this value is exact by definition.

How do I convert watt-hours to kilojoules?

Multiply the number of watt-hours by 3.6. For example, 10 Wh × 3.6 = 36 kJ.

How many watt-hours are in one kilojoule?

One kilojoule equals 0.2777777778 watt-hours. That is the reverse factor, 1 ÷ 3.6.

What is 10 watt-hours in kilojoules?

10 Wh = 36 kJ.

Is this Wh to kJ 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.