Convert Joules to Watt-hours

The J-to-Wh conversion appears often when working with energy data across different unit systems. Energy conversions connect food nutrition labels (calories), electricity bills (kWh), and scientific measurements in joules or BTU.

To convert, multiply the joules value by 0.000277778. Written as an equation: Wh = J × 0.000277778.

One joules equals approximately 0.000278 Wh. This means you can multiply any J value by 0.000278 to get the equivalent in Wh.

Worked example: 5 J = 0.001389 Wh. Enter your own value in the converter above for instant results.

Common mistake: Food calories on nutrition labels are actually kilocalories (kcal), which confuses many people when comparing to joules or watt-hours.

Bookmark this page for quick J to Wh conversions, or use the swap button to reverse the direction and convert Wh back to J.