EngiRef / Energy conversion
Convert Joules to Kilojoules (J to kJ)
1 J = 0.001 kJ. Convert joules to kilojoules with the exact factor, a common-values table and a free converter.
Conversion factor
kJ = J × 0.001
1 J = 0.001 kJ
Multiply by 0.001 kJ to go from joules to kilojoules, or divide by it to come back. The factor and every value below are computed by the same converter that runs at /convert, so this page and the tool cannot disagree.
J to kJ table
| Joules (J) | Kilojoules (kJ) |
|---|---|
| 1 J | 0.001 kJ |
| 2 J | 0.002 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 |
Every figure is computed at build time by the site’s own converter from the energy unit registry. For a value that is not listed, put it into the interactive converter.
Frequently asked questions
How many kilojoules are in one Joule?
One Joule is 0.001 kJ, so 100 J is 0.1 kJ.
What is the formula to convert joules to kilojoules?
kJ = J × 0.001. Multiply the value in joules by 0.001 to get kilojoules.
How do I convert kilojoules back to joules?
J = kJ × 1000, so 1 kJ is 1000 J. The kJ to J page carries the same table in that direction.