Kilojoules to joules
Type a value in kilojoules to see it in joules straight away, or type in the second box to convert back.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Type the value in the kilojoules box.
- Read the result in joules as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
J = kJ × 1,000
Multiply the value in kilojoules by 1,000 to get joules.
Example
To convert 25 kJ to joules: 25 × 1,000 = 25,000 J.
Conversion table
| Kilojoules (kJ) | Joules (J) |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 20 | 20,000 |
| 25 | 25,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 250 | 250,000 |
| 500 | 500,000 |
| 1,000 | 1,000,000 |
About the units
- Kilojoule
- Exactly 1000 joules. It appears on food labels next to the calorie figure.
- Joule
- The SI unit of energy, equal to the work done by a force of one newton moving an object one meter.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many joules are in one kilojoule?
1 kJ = 1,000 J exactly.
How do I convert kilojoules to joules?
Use J = kJ × 1,000. For example, 25 kJ = 25,000 J.
How many kilojoules are in one joule?
1 J = 0.001 kJ.
Which calorie do these converters use?
The thermochemical calorie, exactly 4.184 joules, the factor many countries use to turn kcal into kJ on food labels. The International Table calorie is 4.1868 joules, less than 0.07% larger.
What is the difference between kW and kWh?
A kilowatt is a unit of power, the rate of using energy, while a kilowatt-hour is an amount of energy. A 2 kW heater running for three hours uses 6 kWh.