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Energy
Joules to Kilowatt-hours
Convert joules (J) to kilowatt-hours (kWh). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 J = 2.7778e-7 kWh
Joules to Kilowatt-hours Conversion Table
Common values, ready to copy:
| joules | kilowatt-hours |
|---|---|
| 1 J | 2.7778e-7 kWh |
| 2 J | 5.5556e-7 kWh |
| 5 J | 1.3889e-6 kWh |
| 10 J | 2.7778e-6 kWh |
| 25 J | 6.9444e-6 kWh |
| 50 J | 1.3889e-5 kWh |
| 100 J | 2.7778e-5 kWh |
| 1,000 J | 0.000278 kWh |
Formula
kilowatt-hours = joules × 2.77777778e-7
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About Joules and Kilowatt-hours
Joules (J): The SI unit of energy; named for James Prescott Joule, whose 19th-century experiments established the equivalence of mechanical work and heat. Common uses: Physics calculations, food calorie labeling in metric countries (kilojoules), battery capacity, and chemistry.
Kilowatt-hours (kWh): A thousand watt-hours, or 3.6 MJ; the standard utility billing unit for residential and commercial electricity. Common uses: Electricity bills, residential and EV battery capacity (a typical EV battery is 50-100 kWh), and home solar generation.
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is kilowatt-hours = joules × 2.77777778e-7, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between joules and kilowatt-hours comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.