Convert Joules to Watt-hours
One joule equals 0.000277778 watt-hours. Type any value to convert joules to watt-hours instantly — with a full reference table below.
Convert Joules to Watt-hours
Converted in your browser — nothing you enter is sent anywhere.
How to convert Joules to Watt-hours
To convert joules to watt-hours, multiply by 0.000277778. One joule equals 0.000277778 Wh, and one watt-hour equals 3,600 J.
- Take the value in joules — for example 7.5 J.
- Multiply by 0.000277778 (the number of watt-hours in one joule).
- 7.5 × 0.000277778 = 0.00208333 Wh.
Joules to Watt-hours conversion table
| Joules | Watt-hours |
|---|---|
| 1 J | 0.000277778 Wh |
| 2 J | 0.000555556 Wh |
| 5 J | 0.00138889 Wh |
| 10 J | 0.00277778 Wh |
| 20 J | 0.00555556 Wh |
| 50 J | 0.0138889 Wh |
| 100 J | 0.0277778 Wh |
| 200 J | 0.0555556 Wh |
| 500 J | 0.138889 Wh |
| 1,000 J | 0.277778 Wh |
| 2,000 J | 0.555556 Wh |
| Watt-hours | Joules |
|---|---|
| 1 Wh | 3,600 J |
| 2 Wh | 7,200 J |
| 5 Wh | 18,000 J |
| 10 Wh | 36,000 J |
| 20 Wh | 72,000 J |
| 50 Wh | 180,000 J |
| 100 Wh | 360,000 J |
| 200 Wh | 720,000 J |
| 500 Wh | 1,800,000 J |
| 1,000 Wh | 3,600,000 J |
| 2,000 Wh | 7,200,000 J |
About converting Joules to Watt-hours
Joules (J) and Watt-hours (Wh) are both units of energy. The exact factor is 1 J = 0.000277778 Wh, so multiply by 0.000277778 to go from joules to watt-hours (or divide to go back).
The conversion runs entirely in your browser. Need the reverse? Use the Watt-hours to Joules converter, or the full unit converter for every unit at once.
Real-world energy in joules and watt-hours
| Example | Joules | Watt-hours |
|---|---|---|
| One food Calorie (kcal) | 4,184 J | 1.162222 Wh |
| A 100 W bulb running for one hour | 360,000 J | 100 Wh |
| A smartphone battery (≈19 Wh) | ≈ 69,300 J | ≈ 19.25 Wh |
“≈” marks typical values; the rest are defined or measured figures.
The units
The SI unit of energy: the work done by one newton over one metre.
Used for: Science and food labels (kJ).
One watt for one hour: exactly 3,600 J.
Used for: Battery capacity (power banks, laptops).
The thermochemical calorie is exactly 4.184 J and a kilowatt-hour is exactly 3.6 MJ, so these factors are exact.