How to convert kilojoules to joules
J = kJ × 1,000Multiply the value in kilojoules by 1,000. To go the other way, multiply by 0.001 (or divide by 1,000).
A kilojoule is larger than a joule: one kilojoule contains 1,000 joules.
Worked examples
- 1 kilojoule1 kJ × 1,000 = 1,000 J
- 5 kilojoules5 kJ × 1,000 = 5,000 J
- 10 kilojoules10 kJ × 1,000 = 10,000 J
- 20 kilojoules20 kJ × 1,000 = 20,000 J
- 100 kilojoules100 kJ × 1,000 = 100,000 J
Kilojoules to joules conversion table
Values are calculated by the conversion engine and rounded to 8 significant figures.
| Kilojoules (kJ) | Joules (J) |
|---|---|
| 0.1 kJ | 100 J |
| 0.25 kJ | 250 J |
| 0.5 kJ | 500 J |
| 1 kJ | 1,000 J |
| 2 kJ | 2,000 J |
| 3 kJ | 3,000 J |
| 4 kJ | 4,000 J |
| 5 kJ | 5,000 J |
| 6 kJ | 6,000 J |
| 7 kJ | 7,000 J |
| 8 kJ | 8,000 J |
| 9 kJ | 9,000 J |
| 10 kJ | 10,000 J |
| Kilojoules (kJ) | Joules (J) |
|---|---|
| 12 kJ | 12,000 J |
| 15 kJ | 15,000 J |
| 20 kJ | 20,000 J |
| 25 kJ | 25,000 J |
| 30 kJ | 30,000 J |
| 40 kJ | 40,000 J |
| 50 kJ | 50,000 J |
| 75 kJ | 75,000 J |
| 100 kJ | 100,000 J |
| 250 kJ | 250,000 J |
| 500 kJ | 500,000 J |
| 1,000 kJ | 1,000,000 J |
About the units
Kilojoule (kJ)
One thousand joules. Food labels in Australia and the EU list energy in kJ alongside kcal. One kilojoule equals 1,000 joules (J).
Joule (J)
The SI unit of energy: the work done by a force of one newton over one metre, or one watt for one second. Lifting an apple by one metre takes about 1 J.
Frequently asked questions
How many joules are in one kilojoule?
There are 1,000 joules in one kilojoule, and this value is exact by definition.
How do I convert kilojoules to joules?
Multiply the number of kilojoules by 1,000. For example, 10 kJ × 1,000 = 10,000 J.
How many kilojoules are in one joule?
One joule equals 0.001 kilojoules. That is the reverse factor, 1 ÷ 1,000.
What is 10 kilojoules in joules?
10 kJ = 10,000 J.
Is this kJ to J converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.