Convert Joules to Kilojoules
J to kJ · energy conversion
What are joules and kilojoules?
The joule is the SI unit of energy, the work done by one newton acting over one meter. A kilojoule is 1,000 joules, used for food energy outside the US. For reference: a food Calorie is one kilocalorie (4,184 J), and home electricity is billed in kilowatt-hours.
How to convert joules to kilojoules
1 J = 0.001 kJ. To convert, multiply the number of joules by 0.001. For example, 5 J = 0.005 kJ, and 20 J = 0.02 kJ. To go the other way, multiply kilojoules by 1,000 (since 1 kJ = 1,000 J).
Joules to Kilojoules conversion table
| Joules (J) | Kilojoules (kJ) |
|---|---|
| 1 | 0.001 |
| 10 | 0.01 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1,000 | 1 |
| 2,000 | 2 |
| 5,000 | 5 |
FAQ
What is 1 J in kJ?
1 J = 0.001 kJ. To convert any amount, multiply the number of joules by 0.001.
How do I convert kilojoules back to joules?
Go the other way: 1 kJ = 1,000 J, so multiply kilojoules by 1,000 to get joules.
Is a joule bigger than a kilojoule?
No — 1 J is the smaller unit, equal to 0.001 kJ (it takes 1,000 J to make one kJ).
Are these energy conversions exact?
They use the standard internationally-defined conversion factors. Results are rounded to six significant figures for readability, which is accurate enough for everyday and most technical use.