KJ to J Converter
Type a value in kilojoules to see it in joules as you type, with the exact formula and a reference chart.
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How this was calculated
- 1 kilojoule = 1,000 joules
- 4.184 × 1,000 = 4,184 J
| kJ | J |
|---|---|
| 0.001 kJ | 1 J |
| 0.01 kJ | 10 J |
| 0.1 kJ | 100 J |
| 0.5 kJ | 500 J |
| 1 kJ | 1,000 J |
| 2 kJ | 2,000 J |
| 5 kJ | 5,000 J |
| 10 kJ | 10,000 J |
| 50 kJ | 50,000 J |
| 100 kJ | 100,000 J |
| 500 kJ | 500,000 J |
| 1,000 kJ | 1,000,000 J |
| J | kJ |
|---|---|
| 1 J | 0.001 kJ |
| 10 J | 0.01 kJ |
| 50 J | 0.05 kJ |
| 100 J | 0.1 kJ |
| 250 J | 0.25 kJ |
| 500 J | 0.5 kJ |
| 1,000 J | 1 kJ |
| 2,500 J | 2.5 kJ |
| 4,184 J | 4.184 kJ |
| 5,000 J | 5 kJ |
| 10,000 J | 10 kJ |
| 50,000 J | 50 kJ |
How to convert kilojoules to joules
1 kilojoule = 1,000 joules. To convert kilojoules to joules, multiply by 1,000. A kilojoule is 1,000 joules; food labels in Australia, New Zealand and the EU list energy in kJ. The joule is the SI unit of energy, one newton-meter.
Worked examples
- 1 kilojoule = 1,000 J (1 × 1,000)
- 4.184 kilojoules = 4,184 J (4.184 × 1,000)
- 100 kilojoules = 100,000 J (100 × 1,000)
Where this conversion comes up
Kilojoules are used for food labels outside the US and exercise machines; joules for physics and electrical energy. Physics and chemistry problems mix kilojoules (reaction enthalpies, food energy) with joules (SI base unit). 1 kJ is exactly 1,000 J, and one food Calorie of 4.184 kJ is 4,184 J.
Quick estimate
Move the decimal point three places right: 2.5 kJ = 2,500 J.
Common mistakes
- Dividing instead of multiplying. A joule is smaller than a kilojoule, so the number of joules must come out larger: 1 kilojoule = 1,000 J.
Going the other way? Use the j to kj converter. Related energy converters: kj to calories, kcal to kj, kj to kcal, kwh to mwh.
Frequently asked questions
How do you convert kilojoules to joules?
Multiply the kilojoules by 1,000. For example, 4.184 kilojoules is 4,184 joules.
How many joules are in one kilojoule?
One kilojoule is 1,000 joules. A kilojoule is 1,000 joules; food labels in Australia, New Zealand and the EU list energy in kJ.
What is 100 kilojoules in joules?
100 kilojoules is 100,000 joules.
Is there a quick way to estimate kilojoules to joules?
Move the decimal point three places right: 2.5 kJ = 2,500 J.