A yoctojoule (yJ) is a metric-prefixed unit of energy equal to 10-24 joules, a fraction of a single joule, using the SI yocto prefix.
Yoctojoules to Millijoules
Convert Yoctojoule (yJ) to Millijoule (mJ) instantly with an exact formula, conversion table, and FAQ.
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Convert yoctojoules (yJ) to millijoules (mJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
mJ = yJ × 1.000000000e-21
Results update instantly for Yoctojoules to Millijoules conversions.
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Formula
mJ = yJ × 1.000000000e-21
yJ = mJ × 1.000000000e+21
Conversion table
| 1 yJ | 1.000000e-21 mJ |
| 5 yJ | 5.000000e-21 mJ |
| 10 yJ | 1.000000e-20 mJ |
| 20 yJ | 2.000000e-20 mJ |
| 50 yJ | 5.000000e-20 mJ |
| 100 yJ | 1.000000e-19 mJ |
| 500 yJ | 5.000000e-19 mJ |
| 1000 yJ | 1.000000e-18 mJ |
Related conversions
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How the formula works
Both yoctojoule and millijoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in yoctojoules by 1.000000000e-21 to get millijoules. To reverse the conversion, multiply a millijoule value by 1.000000000e+21 to get back to yoctojoules.
Frequently asked questions
What is Yoctojoule (yJ)?
A yoctojoule (yJ) is a metric-prefixed unit of energy equal to 10-24 joules, a fraction of a single joule, using the SI yocto prefix.
What is Millijoule (mJ)?
A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
How do I convert yoctojoules to millijoules?
Multiply the yoctojoule value by 1.000000000e-21 to get the equivalent in millijoules. For example, 5 yJ × 1.000000000e-21 = 5.000000e-21 mJ.
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 millijoules back to yoctojoules?
Yes. Divide the millijoule value by 1.000000000e-21, or multiply it by 1.000000000e+21, to get yoctojoules.
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About converting yoctojoules to millijoules
A yoctojoule (yJ) is a metric-prefixed unit of energy equal to 10-24 joules, a fraction of a single joule, using the SI yocto prefix. A millijoule (mJ) is a metric-prefixed unit of energy equal to 10-3 joules, a fraction of a single joule, using the SI milli prefix.
Use this calculator to move between yoctojoules and millijoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.