kWh to kJ Converter
Convert kilowatt-hours to kilojoules — one kWh is exactly 3,600 kJ. Results update as you type; exact factors shown.
One kilowatt-hour is 3,600 kilojoules — see the exact factor, not a rounded rule of thumb.
How the kwh to kj converter works
Energy converts through the joule. A thermochemical calorie is exactly 4.184 J, so a food Calorie (kcal) is 4.184 kJ. A kilowatt-hour is exactly 3.6 MJ. A BTU is 1,055.056 J and a US therm is 100,000 BTU.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common energy conversions
| From | To | Units |
|---|---|---|
| 0.1 kWh | 360 kJ | kilowatt-hours to kilojoules |
| 0.25 kWh | 900 kJ | kilowatt-hours to kilojoules |
| 0.5 kWh | 1,800 kJ | kilowatt-hours to kilojoules |
| 1 kWh | 3,600 kJ | kilowatt-hour to kilojoules |
| 2 kWh | 7,200 kJ | kilowatt-hours to kilojoules |
| 3 kWh | 10,800 kJ | kilowatt-hours to kilojoules |
| 5 kWh | 18,000 kJ | kilowatt-hours to kilojoules |
| 10 kWh | 36,000 kJ | kilowatt-hours to kilojoules |
| 20 kWh | 72,000 kJ | kilowatt-hours to kilojoules |
| 50 kWh | 180,000 kJ | kilowatt-hours to kilojoules |
| 100 kWh | 360,000 kJ | kilowatt-hours to kilojoules |
| 1,000 kWh | 3,600,000 kJ | kilowatt-hours to kilojoules |
Units in this converter and their exact factors
| Unit | Symbol | One unit in joules |
|---|---|---|
| joule | J | 1 joule |
| kilojoule | kJ | 1,000 joule |
| megajoule | MJ | 1,000,000 joule |
| calorie (thermochemical) | cal | 4.184 joule |
| kilocalorie (food Calorie) | kcal | 4,184 joule |
| watt-hour | Wh | 3,600 joule |
| kilowatt-hour | kWh | 3,600,000 joule |
| British thermal unit | BTU | 1,055.05585262 joule |
| therm (US) | thm | 105,505,585.262 joule |
| foot-pound | ft·lb | 1.3558179483 joule |
FAQFrequently asked questions about energy conversion
How many kJ in a kWh?
Exactly 3,600 kJ, because a kilowatt for an hour is 1,000 joules per second for 3,600 seconds.
What is 1 kWh in kJ?
3,600 kJ, or 3.6 MJ.
Why do electricity bills use kWh?
Because it is a convenient size: a typical home uses 8 to 30 kWh a day, where the same in joules runs to tens of millions.
How does this relate to food calories?
One kWh is 3,600 kJ, which is about 860 food Calories — roughly a third of a day's eating.
What is a megajoule?
1,000 kJ. Australian gas bills are billed in MJ, where electricity is in kWh.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.