Convert Kilojoule to Joule
Use this free converter to change kilojoules (kJ) into joules (J). Kilojoule and joule both measure energy. As a quick reference, 1 kJ equals 1000 J, and 1 J equals 0.001 kJ.
Free · runs in your browser · no sign-up
Joule (J)
1000
1 kJ = 1000 J
Energy conversion table
| Kilojoule | Joule |
|---|---|
| 0.01 | 10 |
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1000 |
| 2 | 2000 |
| 3 | 3000 |
| 5 | 5000 |
| 10 | 10000 |
| 20 | 20000 |
| 25 | 25000 |
| 50 | 50000 |
| 100 | 100000 |
| 1,000 | 1000000 |
How to convert Kilojoule to Joule
Multiply the kilojoule value by 1000 to get joules.
- Enter the number of kilojoules you want to convert.
- The converter instantly shows the equivalent value in joules.
- Worked example: 15 kJ × 1000 = 15000 J.
- Use the swap button to reverse the conversion (joule to kilojoule).
About these units
Kilojoule (kJ)
- Definition
- A kilojoule (kJ) is 1,000 joules, a practical size for food energy and mechanical work.
- History
- It is a metric multiple of the joule.
- Current use
- Kilojoules express food energy on nutrition labels in many countries.
Joule (J)
- Definition
- The joule (J) is the SI unit of energy, the work done by a force of one newton over one meter.
- History
- Named after physicist James Prescott Joule, who studied the link between heat and work.
- Current use
- Joules measure energy, work, and heat throughout science and engineering.
Frequently asked questions
How many joules are in a kilojoule?
There are 1000 J in 1 kJ. To convert, multiply the number of kilojoules by 1000.
How do I convert kilojoules to joules?
Multiply the kilojoule value by 1000 to get joules. For example, 10 kJ = 10000 J.
Is this kilojoule-to-joule converter free?
Yes. This converter is completely free, runs entirely in your browser, and requires no sign-up. Your inputs never leave your device.
Convert Kilojoule to other energy units
| Unit | 1 Kilojoule equals |
|---|---|
| Joule (J) | 1000 J |
| Calorie (cal) | 239.00574 cal |
| Kilocalorie (kcal) | 0.23900574 kcal |
| Watt Hour (Wh) | 0.27777778 Wh |
| Kilowatt Hour (kWh) | 0.00027777778 kWh |
| Electronvolt (eV) | 6.2415e+21 eV |
| British Thermal Unit (BTU) | 0.94781712 BTU |
| Foot-Pound (ft·lb) | 737.56215 ft·lb |