A femtojoule (fJ) is a metric-prefixed unit of energy equal to 10-15 joules, a fraction of a single joule, using the SI femto prefix.
Femtojoules to Millijoules
Convert Femtojoule (fJ) to Millijoule (mJ) instantly with an exact formula, conversion table, and FAQ.
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Convert femtojoules (fJ) 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 = fJ × 1.000000000e-12
Results update instantly for Femtojoules to Millijoules conversions.
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Formula
mJ = fJ × 1.000000000e-12
fJ = mJ × 1000000000000
Conversion table
| 1 fJ | 1.000000e-12 mJ |
| 5 fJ | 5.000000e-12 mJ |
| 10 fJ | 1.000000e-11 mJ |
| 20 fJ | 2.000000e-11 mJ |
| 50 fJ | 5.000000e-11 mJ |
| 100 fJ | 1.000000e-10 mJ |
| 500 fJ | 5.000000e-10 mJ |
| 1000 fJ | 1.000000e-09 mJ |
Related conversions
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How the formula works
Both femtojoule and millijoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in femtojoules by 1.000000000e-12 to get millijoules. To reverse the conversion, multiply a millijoule value by 1000000000000 to get back to femtojoules.
Frequently asked questions
What is Femtojoule (fJ)?
A femtojoule (fJ) is a metric-prefixed unit of energy equal to 10-15 joules, a fraction of a single joule, using the SI femto 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 femtojoules to millijoules?
Multiply the femtojoule value by 1.000000000e-12 to get the equivalent in millijoules. For example, 5 fJ × 1.000000000e-12 = 5.000000e-12 mJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e-12 is an exact, non-rounded value.
Can I convert millijoules back to femtojoules?
Yes. Divide the millijoule value by 1.000000000e-12, or multiply it by 1000000000000, to get femtojoules.
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About converting femtojoules to millijoules
A femtojoule (fJ) is a metric-prefixed unit of energy equal to 10-15 joules, a fraction of a single joule, using the SI femto 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 femtojoules 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.