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 Joules
Convert Femtojoule (fJ) to Joule (J) instantly with an exact formula, conversion table, and FAQ.
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Convert femtojoules (fJ) to joules (J) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
J = fJ × 1.000000000e-15
Results update instantly for Femtojoules to Joules conversions.
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Formula
J = fJ × 1.000000000e-15
fJ = J × 1000000000000000
Conversion table
| 1 fJ | 1.000000e-15 J |
| 5 fJ | 5.000000e-15 J |
| 10 fJ | 1.000000e-14 J |
| 20 fJ | 2.000000e-14 J |
| 50 fJ | 5.000000e-14 J |
| 100 fJ | 1.000000e-13 J |
| 500 fJ | 5.000000e-13 J |
| 1000 fJ | 1.000000e-12 J |
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How the formula works
Both femtojoule and joule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in femtojoules by 1.000000000e-15 to get joules. To reverse the conversion, multiply a joule value by 1000000000000000 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 Joule (J)?
The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
How do I convert femtojoules to joules?
Multiply the femtojoule value by 1.000000000e-15 to get the equivalent in joules. For example, 5 fJ × 1.000000000e-15 = 5.000000e-15 J.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 1.000000000e-15 is an exact, non-rounded value.
Can I convert joules back to femtojoules?
Yes. Divide the joule value by 1.000000000e-15, or multiply it by 1000000000000000, to get femtojoules.
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About converting femtojoules to joules
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. The joule (J) is the SI derived unit of energy, equal to the work done when a force of one newton acts over one meter.
Use this calculator to move between femtojoules and joules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.