Joules to Kilojoules
Convert joules to kilojoules (J to kJ). 1 J = 0.001 kJ. Use the calculator, formula and conversion table.
How to convert joules to kilojoules
Multiply the amount in joules by 0.001 to get kilojoules. The displayed factor and results are rounded to 12 significant digits.
kJ = J × 0.001Worked example
1 J = 0.001 kJ. Change the amount in the calculator above to use your own value.
Units and assumptions
A watt-hour is 3,600 joules. Calories use the thermochemical definition (4.184 J); BTU uses the International Table definition.
Calculator results use floating-point arithmetic and are rounded for display. The reference table below uses up to 12 significant digits.
Joules to Kilojoules table
| Joules (J) | Kilojoules (kJ) |
|---|---|
| 0 | 0 |
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 100 | 0.1 |
| 1,000 | 1 |
About this conversion
What is the formula for joules to kilojoules?
kJ = J × 0.001. Multiply the amount in joules by 0.001 to get kilojoules. The displayed factor and results are rounded to 12 significant digits.
How do I convert back to joules?
Use the kilojoules to joules calculator to reverse this conversion. You can also use Swap units in the calculator above.
Can I use a different pair of units?
Choose another unit in the calculator, or open the energy converter to browse all supported pairs.