⚡ Energy
joules to watt-hours Converter
Convert joules to watt-hours instantly with a reference conversion table.
Quick answer: To convert joules to watt-hours, multiply by 0.000277778. For example, 1 joules = 0.000277778 watt-hours. Use the calculator below for any value.
joules to watt-hours
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Common conversions
| joules | watt-hours |
|---|
Formula:
How to convert joules to watt-hours
1
Enter your value
Type the number of joules you want to convert into the left box. The result in watt-hours appears instantly in the right box. You can also type into the right box to convert in the other direction.
2
Use the swap button
Click the ⇄ Swap button to reverse the conversion — watt-hours to joules. Your current value carries across so you don't have to re-enter anything.
3
About joules and watt-hours
joules and watt-hours are common energy measurements.
💡 Did you know?
3,600 J = 1 Wh. A single chocolate biscuit (100 kcal = 418,400 J = 116 Wh) contains more energy than a fully-charged phone battery (4,500 mAh at 3.7V = 16.65 Wh). Calories to watt-hours: kcal × 1.163.
📊 Common conversions at a glance
| joules | watt-hours |
|---|---|
| 1 | 0.0002778 |
| 3600 | 1 |
| 10000 | 2.778 |
| 100000 | 27.78 |
| 1000000 | 277.8 |
| 10000000 | 2778 |
Reviewed for 2026. joules ↔ watt-hours conversion factor verified against published reference data. Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project.