Joules to kWh Converter
Convert joule to kilowatt-hour instantly. 1 J = 2.777777778e-7 kWh, worked steps and a full reference table.
How to use it
- Type the value in joule — the result updates as you type.
- Use Swap to flip the direction, or change either dropdown to convert between any two units.
- Click the result to copy it. The URL updates too, so you can bookmark or share the exact conversion.
Examples
| 1 J | 2.777777778e-7 kWh |
| 5 J | 0.000001388888889 kWh |
| 10 J | 0.000002777777778 kWh |
| 100 J | 0.00002777777778 kWh |
One joule equals 2.7778e-7 kilowatt-hours (kWh). To convert joules to kilowatt-hours, multiply by 2.7778e-7; to go back the other way, multiply by 3600000 instead.
The converter above does it as you type and shows the working underneath, so you can check the arithmetic rather than take the number on trust.
What joules and kilowatt-hours actually measure
Joule (J) — The joule is the SI unit of energy — one watt for one second. Physics, mechanical work and food energy in most of the world.
Kilowatt-hour (kWh) — A kilowatt-hour is a thousand watt-hours, or 3.6 megajoules. Electricity billing everywhere, and EV battery capacity.
Joules to kWh conversion table
The most common values, worked out in advance. Anything not listed can be typed straight into the converter.
| J | kWh |
|---|---|
| 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 |
How to convert joules to kilowatt-hours by hand
Multiply the number of joules by 2.7778e-7.
For example, 25 J × 2.7778e-7 = 6.9444e-6 kWh.
Going the other way, divide by 2.7778e-7 — or multiply by 3600000, which is the same thing and easier to do in your head.
Everything runs in your browser
There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.
Questions people ask
How many kWh are in 1 J?
1 J equals exactly 2.777777778e-7 kWh. Multiply any value in joule by 2.777777778e-7 to get kilowatt-hour.
Is anything uploaded to a server?
No. The whole calculation happens in your browser. Nothing is sent anywhere, and the page keeps working offline once loaded.
Last updated 18 August 2026