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 Megajoules
Convert Millijoule (mJ) to Megajoule (MJ) instantly with an exact formula, conversion table, and FAQ.
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Convert millijoules (mJ) to megajoules (MJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
MJ = mJ × 1.000000000e-09
Results update instantly for Millijoules to Megajoules conversions.
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Formula
MJ = mJ × 1.000000000e-09
mJ = MJ × 1000000000
Conversion table
| 1 mJ | 1.000000e-09 MJ |
| 5 mJ | 5.000000e-09 MJ |
| 10 mJ | 1.000000e-08 MJ |
| 20 mJ | 2.000000e-08 MJ |
| 50 mJ | 5.000000e-08 MJ |
| 100 mJ | 1.000000e-07 MJ |
| 500 mJ | 5.000000e-07 MJ |
| 1000 mJ | 0.000001 MJ |
Related conversions
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How the formula works
Both millijoule and megajoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in millijoules by 1.000000000e-09 to get megajoules. To reverse the conversion, multiply a megajoule value by 1000000000 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 Megajoule (MJ)?
A megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
How do I convert millijoules to megajoules?
Multiply the millijoule value by 1.000000000e-09 to get the equivalent in megajoules. For example, 5 mJ × 1.000000000e-09 = 5.000000e-09 MJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e-09 is an exact, non-rounded value.
Can I convert megajoules back to millijoules?
Yes. Divide the megajoule value by 1.000000000e-09, or multiply it by 1000000000, to get millijoules.
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About converting millijoules to megajoules
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 megajoule (MJ) is a metric-prefixed unit of energy equal to 106 joules, using the SI mega prefix.
Use this calculator to move between millijoules and megajoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.