A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States.
Kilojoules to Attojoules
Convert Kilojoule (kJ) to Attojoule (aJ) instantly with an exact formula, conversion table, and FAQ.
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Convert kilojoules (kJ) to attojoules (aJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix.
aJ = kJ × 1.000000000e+21
Results update instantly for Kilojoules to Attojoules conversions.
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Formula
aJ = kJ × 1.000000000e+21
kJ = aJ × 1.000000000e-21
Conversion table
| 1 kJ | 1.000000e+21 aJ |
| 5 kJ | 5.000000e+21 aJ |
| 10 kJ | 1.000000e+22 aJ |
| 20 kJ | 2.000000e+22 aJ |
| 50 kJ | 5.000000e+22 aJ |
| 100 kJ | 1.000000e+23 aJ |
| 500 kJ | 5.000000e+23 aJ |
| 1000 kJ | 1.000000e+24 aJ |
Related conversions
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How the formula works
Both kilojoule and attojoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in kilojoules by 1.000000000e+21 to get attojoules. To reverse the conversion, multiply a attojoule value by 1.000000000e-21 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 Attojoule (aJ)?
A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix.
How do I convert kilojoules to attojoules?
Multiply the kilojoule value by 1.000000000e+21 to get the equivalent in attojoules. For example, 5 kJ × 1.000000000e+21 = 5.000000e+21 aJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e+21 is an exact, non-rounded value.
Can I convert attojoules back to kilojoules?
Yes. Divide the attojoule value by 1.000000000e+21, or multiply it by 1.000000000e-21, to get kilojoules.
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About converting kilojoules to attojoules
A kilojoule (kJ) equals 1,000 joules and is commonly used on nutrition labels outside the United States. A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix.
Use this calculator to move between kilojoules and attojoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.