Kilojoules to Joules Converter
One Kilojoule equals 1000 Joules (1 kJ = 1000 J). Multiply a Kilojoule value by 1000 to get the equivalent in Joules. The calculator is above; the formula and worked examples are below.
Formula
J = kJ × 1000
Multiply the Kilojoule value by 1000 to get the equivalent value in Joules.
Example Conversions
1 Kilojoule (kJ)
1000 Joule (J)
5 Kilojoule (kJ)
5000 Joule (J)
10 Kilojoule (kJ)
10000 Joule (J)
25 Kilojoule (kJ)
25000 Joule (J)
100 Kilojoule (kJ)
100000 Joule (J)
Conversion Table
| Kilojoule (kJ) | Joule (J) |
|---|---|
| 0.1 | 100 |
| 0.5 | 500 |
| 1 | 1000 |
| 2 | 2000 |
| 5 | 5000 |
| 10 | 10000 |
| 25 | 25000 |
| 50 | 50000 |
| 100 | 100000 |
| 250 | 250000 |
| 500 | 500000 |
| 1000 | 1000000 |
How to Convert Manually
Use these steps to convert Kilojoule values to Joule without the calculator.
- Write down the value in Kilojoule (kJ) that you want to convert.
- Multiply that value by 1000.
- For example, 10 Kilojoules × 1000 = 10000 Joules.
- Label the result as Joule (J).
Relative Size Comparison
This chart shows the visual difference in size between exactly one Kilojoule and one Joule.
About Kilojoule and Joule
The kilojoule is 1,000 joules. Food energy in Australia, Europe, and most metric countries is labeled in kilojoules alongside or instead of calories. The joule is the SI derived unit of energy, the work done by a force of one newton over one meter. Physics, chemistry, and food labeling outside the US build on it. One Kilojoule equals 1000 Joules (1 kJ = 1000 J). Kilojoule is used in food labels outside the US and in exercise energy expenditure. Joule is used in physics and engineering calculations.
Precision and Rounding:Energy factors mix exact definitions (1 kWh = 3,600,000 J; 1 cal = 4.184 J thermochemical) with measured conventions (1 BTU ≈ 1,055.056 J). Nutrition and utility bills round to whole units; engineering heat calculations should keep the full factor until the final step.
Conversion factors per NIST Special Publication 811 and the BIPM SI Brochure (9th edition) (reference).
Worked Example
15Kilojoules equals15000Joules.
15 kJ × 1000 = 15000 J
FAQ
How do I convert Kilojoule to Joule?
Multiply the Kilojoule value by 1000 to get the equivalent value in Joules.
What is the formula for Kilojoule to Joule?
The formula is J = kJ × 1000.
How many Joules are in 1 Kilojoule?
1 Kilojoule equals 1000 Joules.
Can I convert Joule back to Kilojoule?
Yes. 1 Joule equals 0.001 Kilojoules, and the related converter can reverse the calculation.
What are common names for Kilojoule and Joule?
Kilojoule is shown as kJ and may also be searched as kilojoule, kilojoules. Joule is shown as J and may also be searched as joule, joules.
Was this page helpful?
Let us know if this converter met your needs.