A microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro prefix.
Microjoules to Millijoules
Convert Microjoule (uJ) to Millijoule (mJ) instantly with an exact formula, conversion table, and FAQ.
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Convert microjoules (uJ) 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 = uJ × 0.001
Results update instantly for Microjoules to Millijoules conversions.
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Formula
mJ = uJ × 0.001
uJ = mJ × 1000
Conversion table
| 1 uJ | 0.001000 mJ |
| 5 uJ | 0.005000 mJ |
| 10 uJ | 0.010000 mJ |
| 20 uJ | 0.020000 mJ |
| 50 uJ | 0.050000 mJ |
| 100 uJ | 0.100000 mJ |
| 500 uJ | 0.500000 mJ |
| 1000 uJ | 1 mJ |
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How the formula works
Both microjoule and millijoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in microjoules by 0.001 to get millijoules. To reverse the conversion, multiply a millijoule value by 1000 to get back to microjoules.
Frequently asked questions
What is Microjoule (uJ)?
A microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro 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 microjoules to millijoules?
Multiply the microjoule value by 0.001 to get the equivalent in millijoules. For example, 5 uJ × 0.001 = 0.005000 mJ.
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 millijoules back to microjoules?
Yes. Divide the millijoule value by 0.001, or multiply it by 1000, to get microjoules.
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About converting microjoules to millijoules
A microjoule (uJ) is a metric-prefixed unit of energy equal to 10-6 joules, a fraction of a single joule, using the SI micro 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 microjoules 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.