Convert joules to watt-hours
Joule (J) to watt-hour (Wh). One joule equals 0.000278 watt-hours.
Formula
Joule to watt-hour conversion table
| Joules | Watt-hours | Watt-hours | Joules |
|---|---|---|---|
| 1 J | 0.000278 Wh | 1 Wh | 3600 J |
| 2 J | 0.000556 Wh | 2 Wh | 7200 J |
| 3 J | 0.000833 Wh | 3 Wh | 10800 J |
| 5 J | 0.001389 Wh | 5 Wh | 18000 J |
| 10 J | 0.002778 Wh | 10 Wh | 36000 J |
| 20 J | 0.005556 Wh | 20 Wh | 72000 J |
| 50 J | 0.013889 Wh | 50 Wh | 180000 J |
| 100 J | 0.027778 Wh | 100 Wh | 360000 J |
| 500 J | 0.138889 Wh | 500 Wh | 1800000 J |
| 1000 J | 0.277778 Wh | 1000 Wh | 3600000 J |
To convert joules to watt-hours, divide the number of joules by 3600. One joule equals 0.000278 watt-hours, and one watt-hour equals 3600 joules, so the relationship is fixed and exact. As a worked example, 10 J comes to 0.002778 Wh. Enter your own figure in the converter above to get an instant answer, or use the swap button to flip the direction. This is a energy conversion, and like every tool on UnitGlide it runs locally in your browser with no account or upload required. The table further down shows a range of common joule values already worked out in watt-hours, plus the reverse watt-hour to joule direction, which is handy for quick reference or double-checking a result by hand.
Frequently asked questions
How many watt-hours are in a joule?
One joule equals 0.000278 watt-hours. The ratio is constant, so you can multiply any number of joules by 0.000278 to get watt-hours.
What is the formula to convert joules to watt-hours?
Use watt-hours = joules ÷ 3600. UnitGlide applies this exact formula for every value, so results stay accurate across the whole range.
How do I convert watt-hours back to joules?
Go the other way by using one watt-hour equals 3600 joules. You can also press the swap button in the converter above to flip the direction in one click.
Is this joule to watt-hour converter accurate?
Yes. It uses internationally defined SI conversion factors, as maintained by the BIPM, and all math runs in your browser so nothing is rounded away on a server. For everyday use the displayed precision is more than enough.