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.
Joules to Kilojoules
Convert Joule (J) to Kilojoule (kJ) instantly with an exact formula, conversion table, and FAQ.
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Convert joules (J) to kilojoules (kJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
kJ = J × 0.001
Results update instantly for Joules to Kilojoules conversions.
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Formula
kJ = J × 0.001
J = kJ × 1000
Conversion table
| 1 J | 0.001000 kJ |
| 5 J | 0.005000 kJ |
| 10 J | 0.010000 kJ |
| 20 J | 0.020000 kJ |
| 50 J | 0.050000 kJ |
| 100 J | 0.100000 kJ |
| 500 J | 0.500000 kJ |
| 1000 J | 1 kJ |
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How the formula works
Both joule and kilojoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in joules by 0.001 to get kilojoules. To reverse the conversion, multiply a kilojoule value by 1000 to get back to joules.
Frequently asked questions
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.
What is Kilojoule (kJ)?
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
How do I convert joules to kilojoules?
Multiply the joule value by 0.001 to get the equivalent in kilojoules. For example, 5 J × 0.001 = 0.005000 kJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 0.001 is an exact, non-rounded value.
Can I convert kilojoules back to joules?
Yes. Divide the kilojoule value by 0.001, or multiply it by 1000, to get joules.
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About converting joules to kilojoules
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. A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
Use this calculator to move between joules and kilojoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.