Joules to Watt-hours Converter
1 joule ≈ 0.000277777778 watt-hours
1 joule equals 0.000277778 watt-hours
How to convert joules to watt-hours
Calories here are thermochemical (4.184 J), while BTU uses the International Table definition. A kilowatt-hour is energy (3.6 MJ), not power; a food Calorie is a kilocalorie.
Wh = J ÷ 3600One watt-hour corresponds to 3600 joules, so divide by that figure. Displayed constants may be rounded; the converter uses the stored factor before rounding the result.
0.00277778 Wh ≈ 10 ÷ 3600Joules to watt-hours conversion table
Common values in joules, converted to watt-hours.
| Joules (J) | Watt-hours (Wh) |
|---|---|
| 1 | 0.00027777778 |
| 2 | 0.00055555556 |
| 3 | 0.00083333333 |
| 4 | 0.0011111111 |
| 5 | 0.0013888889 |
| 10 | 0.0027777778 |
| 20 | 0.0055555556 |
| 25 | 0.0069444444 |
| 50 | 0.013888889 |
| 100 | 0.027777778 |
| 250 | 0.069444444 |
| 500 | 0.13888889 |
| 1,000 | 0.27777778 |
About these units
jouleJ
The SI derived unit of energy: one newton acting through one metre.
watt-hourWh
One watt sustained for one hour: exactly 3,600 joules.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.