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.
Millijoules to Exajoules
Convert Millijoule (mJ) to Exajoule (EJ) instantly with an exact formula, conversion table, and FAQ.
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Convert millijoules (mJ) to exajoules (EJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A exajoule (EJ) is a metric-prefixed unit of energy equal to 1018 joules, using the SI exa prefix.
EJ = mJ × 1.000000000e-21
Results update instantly for Millijoules to Exajoules conversions.
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Formula
EJ = mJ × 1.000000000e-21
mJ = EJ × 1.000000000e+21
Conversion table
| 1 mJ | 1.000000e-21 EJ |
| 5 mJ | 5.000000e-21 EJ |
| 10 mJ | 1.000000e-20 EJ |
| 20 mJ | 2.000000e-20 EJ |
| 50 mJ | 5.000000e-20 EJ |
| 100 mJ | 1.000000e-19 EJ |
| 500 mJ | 5.000000e-19 EJ |
| 1000 mJ | 1.000000e-18 EJ |
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How the formula works
Both millijoule and exajoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in millijoules by 1.000000000e-21 to get exajoules. To reverse the conversion, multiply a exajoule value by 1.000000000e+21 to get back to millijoules.
Frequently asked questions
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.
What is Exajoule (EJ)?
A exajoule (EJ) is a metric-prefixed unit of energy equal to 1018 joules, using the SI exa prefix.
How do I convert millijoules to exajoules?
Multiply the millijoule value by 1.000000000e-21 to get the equivalent in exajoules. For example, 5 mJ × 1.000000000e-21 = 5.000000e-21 EJ.
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 exajoules back to millijoules?
Yes. Divide the exajoule value by 1.000000000e-21, or multiply it by 1.000000000e+21, to get millijoules.
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About converting millijoules to exajoules
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. A exajoule (EJ) is a metric-prefixed unit of energy equal to 1018 joules, using the SI exa prefix.
Use this calculator to move between millijoules and exajoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.