Joules to Watt Hours converter
Convert joules (J) to watt hours (Wh) — results update instantly as you type.
Joules to Watt Hours
To
1 J = 0.00027778 Wh
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How to convert Joules to Watt Hours
Energy appears as joules in physics, calories in nutrition, and kilowatt hours on electricity bills. All measure the same thing — the capacity to do work — just at very different scales.
Everything converts through the joule. One (small) calorie is exactly 4.184 joules, a food Calorie (kcal) is 4,184 joules, and one kilowatt hour is exactly 3.6 million joules.
Formula
J × 0.0002777778 = Wh
Multiply your joules value by 0.0002777778 to get watt hours. For the reverse, divide by the same factor.
Joules to Watt Hours conversion table
| Joules | Watt Hours |
|---|---|
| 1 J | 0.000278 Wh |
| 2 J | 0.000556 Wh |
| 5 J | 0.001389 Wh |
| 10 J | 0.002778 Wh |
| 25 J | 0.006944 Wh |
| 100 J | 0.027778 Wh |
Common use cases
- Comparing food energy (kcal) with exercise burn
- Understanding electricity bills in kWh
- Physics and engineering calculations in joules
- Battery capacity comparisons in watt hours
Frequently asked questions
A food Calorie (capital C) is actually a kilocalorie — 1,000 small calories. Nutrition labels always mean kilocalories.