joule to watt-hour
Convert joule (J) to watt-hour (Wh). Use an editable energy converter, conversion formula, and reference table.
1 J = 0.0002777777778 Wh
Conversion formula
One joule equals 0.0002777777778 watt-hour. Multiply your value in joule by this factor to get watt-hour. For the reverse conversion, divide by the same factor.
Worked example
To convert 5 joule:5 × 0.0002777777778 = 0.001388888889 Wh
Conversion table
| joule (J) | watt-hour (Wh) |
|---|---|
| 0.01 | 0.000002777777778 |
| 0.1 | 0.00002777777778 |
| 1 | 0.0002777777778 |
| 2 | 0.0005555555556 |
| 5 | 0.001388888889 |
| 10 | 0.002777777778 |
| 25 | 0.006944444444 |
| 50 | 0.01388888889 |
| 100 | 0.02777777778 |
| 1000 | 0.2777777778 |
About these measurements
Energy can be transferred through work, heating, or electrical processes.
The base reference used here is the joule. One joule is 1 base units; one watt-hour is 3,600 base units.
Important distinctions
Calorie and BTU definitions vary. These pages label thermochemical calories and International Table BTUs explicitly.
Precision
The converter uses stored conversion factors and floating-point arithmetic. Results display up to ten significant digits, switching to scientific notation for very small or large values. Keep the precision of your original measurement when reporting results.
Common questions
How do I convert J to Wh?
Multiply the quantity in J by 0.0002777777778. You can also type the value into the converter above.
Can I reverse the conversion?
Yes. Use the swap button or open the watt-hour to joule converter.
Reference
NIST Guide to the SI — conversion factors and prefix conventions. SI prefixes scale units by powers of ten; the dimension-specific notes above describe the assumptions used on this page.
