Joules to Watt-hours Converter
Convert joule to watt-hour instantly. Type a value below — the result updates as you type.
When you need to convert joule to watt-hour
Energy conversions appear on nutrition labels, utility bills and appliance specs, letting you compare food energy, electricity use and heating output on a common scale.
Typical values: 0.5 J is about 0.000138889 Wh, and 100 J works out to roughly 0.0278 Wh. Because the ratio is fixed at 0.000277778, you can scale any amount linearly — doubling the joules doubles the watt-hours.
Food packaging, power meters and heating equipment each prefer different energy units, so converting makes them directly comparable.
How to convert joule to watt-hour
One joule equals 0.000277778 watt-hours. To convert, multiply the number of joules by 0.000277778:
watt-hours = joules × 0.000277778
For example, 10 joules × 0.000277778 = 0.0028 watt-hours.
Joules to watt-hours conversion table
| Energy (J) | Watt-hours (Wh) |
|---|---|
| 1 J | 0.000277778 Wh |
| 2 J | 0.000555556 Wh |
| 3 J | 0.000833333 Wh |
| 5 J | 0.0014 Wh |
| 10 J | 0.0028 Wh |
| 20 J | 0.0056 Wh |
| 50 J | 0.0139 Wh |
| 100 J | 0.0278 Wh |
FAQ
How many watt-hours are in a joule?
One joule = 0.000277778 watt-hours.
How do I convert watt-hours back to joules?
Divide by 0.000277778, or use the watt-hours to joules converter.