Kilojoules to Joules Converter
Convert kilojoule to joule instantly. Type a value below — the result updates as you type.
When you need to convert kilojoule to joule
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 kJ is about 500 J, and 5 kJ works out to roughly 5000 J. Because the ratio is fixed at 1000, you can scale any amount linearly — doubling the kilojoules doubles the joules.
Food packaging, power meters and heating equipment each prefer different energy units, so converting makes them directly comparable.
How to convert kilojoule to joule
One kilojoule equals 1000 joules. To convert, multiply the number of kilojoules by 1000:
joules = kilojoules × 1000
For example, 10 kilojoules × 1000 = 10000 joules.
Kilojoules to joules conversion table
| Energy (kJ) | Joules (J) |
|---|---|
| 1 kJ | 1000 J |
| 2 kJ | 2000 J |
| 3 kJ | 3000 J |
| 5 kJ | 5000 J |
| 10 kJ | 10000 J |
| 20 kJ | 20000 J |
| 50 kJ | 50000 J |
| 100 kJ | 100000 J |
FAQ
How many joules are in a kilojoule?
One kilojoule = 1000 joules.
How do I convert joules back to kilojoules?
Divide by 1000, or use the joules to kilojoules converter.