Joules to Kilojoules
Convert joules (J) to kilojoules (kJ) instantly — with formula and reference table.
J
kJ
Quick answer: 1 J = 0.001 kJ. To convert joules to kilojoules, multiply by J × 0.001.
Converting joules to kilojoules
This converter changes a value in joules (J) into kilojoules (kJ). One joule equals 0.001 kJ. One kilojoule equals 1,000 joules, so converting joules to kilojoules means dividing by 1,000. The conversion runs entirely in your browser — enter a value and the result updates instantly, in either direction.
Formula
kJ = J × 0.001
Example
Convert 10 J to kJ: 10 × 0.001 = 0.01 kJ.
Joules to Kilojoules conversion table
| Joules (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 |
| 25 J | 0.025 kJ |
| 50 J | 0.05 kJ |
| 100 J | 0.1 kJ |
How to use this converter
- Enter a value in the joules (J) field.
- Read the converted value in kilojoules (kJ) below.
- Type into the kJ field instead to convert in reverse, or use the swap button.
Frequently asked questions
How many kilojoules is 1,000 joules?
1,000 joules equals exactly 1 kilojoule.
How do I convert 5,000 J to kJ?
5,000 divided by 1,000 = 5 kJ.
Why are food labels in kilojoules?
The EU and Australia require energy on labels in kilojoules; the US uses Calories (kcal).