Joules to Kilojoules Converter
Convert joule to kilojoule instantly. Type a value below — the result updates as you type.
When you need to convert joule to kilojoule
Energy conversions appear on nutrition labels, utility bills and appliance specs, letting you compare food energy, electricity use and heating output on a common scale.
Typical values: 0.5 J is about 0.0005 kJ, and 100 J works out to roughly 0.1 kJ. Because the ratio is fixed at 0.001, you can scale any amount linearly — doubling the joules doubles the kilojoules.
Food packaging, power meters and heating equipment each prefer different energy units, so converting makes them directly comparable.
How to convert joule to kilojoule
One joule equals 0.001 kilojoules. To convert, multiply the number of joules by 0.001:
kilojoules = joules × 0.001
For example, 10 joules × 0.001 = 0.01 kilojoules.
Joules to kilojoules conversion table
| Energy (J) | Kilojoules (kJ) |
|---|---|
| 1 J | 0.001 kJ |
| 2 J | 0.002 kJ |
| 3 J | 0.003 kJ |
| 5 J | 0.005 kJ |
| 10 J | 0.01 kJ |
| 20 J | 0.02 kJ |
| 50 J | 0.05 kJ |
| 100 J | 0.1 kJ |
FAQ
How many kilojoules are in a joule?
One joule = 0.001 kilojoules.
How do I convert kilojoules back to joules?
Divide by 0.001, or use the kilojoules to joules converter.