Joules to Kilojoules formula
kilojoules = joules × 0.001
Multiply the number of joules by 0.001 to get kilojoules. To go the other way, multiply by 1,000 instead, or use the kj to joules converter.
Joules to Kilojoules conversion table
Common joules to kj values, rounded for reading. The converter above keeps full precision.
| Joules | Kilojoules |
|---|---|
| 1 J | 0.001 kJ |
| 2 J | 0.002 kJ |
| 3 J | 0.003 kJ |
| 4 J | 0.004 kJ |
| 5 J | 0.005 kJ |
| 10 J | 0.01 kJ |
| 15 J | 0.015 kJ |
| 20 J | 0.02 kJ |
| 25 J | 0.025 kJ |
| 50 J | 0.05 kJ |
| 75 J | 0.075 kJ |
| 100 J | 0.1 kJ |
| 250 J | 0.25 kJ |
| 500 J | 0.5 kJ |
| 1,000 J | 1 kJ |
Worked example
To convert 10 J to kilojoules, multiply by 0.001: the result is 0.01 kJ. A nutritional Calorie is a kilocalorie, equal to 4,184 joules. The smaller scientific calorie equals 4.184 joules.
Frequently asked questions
How many kilojoules are in a joule?
One joule equals 0.001 kilojoules (1 J = 0.001 kJ).
What is 10 joules in kilojoules?
10 J converts to 0.01 kJ. Enter any other value in the converter above to see it recalculated instantly.
How do I convert kilojoules back to joules?
Reverse the calculation: one kilojoule equals 1,000 joules. You can also swap the units in the converter or open the kj to joules page.
Related energy conversions
Need a different pair? Open the full energy converter to choose any two units.