A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
Kilojoules to Joules
Convert Kilojoule (kJ) to Joule (J) instantly with an exact formula, conversion table, and FAQ.
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Convert kilojoules (kJ) to joules (J) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
J = kJ × 1000
Results update instantly for Kilojoules to Joules conversions.
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Formula
J = kJ × 1000
kJ = J × 0.001
Conversion table
| 1 kJ | 1000 J |
| 5 kJ | 5000 J |
| 10 kJ | 10000 J |
| 20 kJ | 20000 J |
| 50 kJ | 50000 J |
| 100 kJ | 100000 J |
| 500 kJ | 500000 J |
| 1000 kJ | 1.000000e+06 J |
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How the formula works
Both kilojoule and joule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in kilojoules by 1000 to get joules. To reverse the conversion, multiply a joule value by 0.001 to get back to kilojoules.
Frequently asked questions
What is Kilojoule (kJ)?
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
What is Joule (J)?
The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
How do I convert kilojoules to joules?
Multiply the kilojoule value by 1000 to get the equivalent in joules. For example, 5 kJ × 1000 = 5000 J.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1000 is an exact, non-rounded value.
Can I convert joules back to kilojoules?
Yes. Divide the joule value by 1000, or multiply it by 0.001, to get kilojoules.
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About converting kilojoules to joules
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States. The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
Use this calculator to move between kilojoules and joules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.