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 Kilowatt hours
Convert Femtojoule (fJ) to Kilowatt-hour (kWh) instantly with an exact formula, conversion table, and FAQ.
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Convert femtojoules (fJ) to kilowatt hours (kWh) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A kilowatt-hour (kWh) is the standard billing unit for electricity, equal to 1,000 watts sustained for one hour.
kWh = fJ × 2.777777778e-22
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Formula
kWh = fJ × 2.777777778e-22
fJ = kWh × 3.600000000e+21
Conversion table
| 1 fJ | 2.777778e-22 kWh |
| 5 fJ | 1.388889e-21 kWh |
| 10 fJ | 2.777778e-21 kWh |
| 20 fJ | 5.555556e-21 kWh |
| 50 fJ | 1.388889e-20 kWh |
| 100 fJ | 2.777778e-20 kWh |
| 500 fJ | 1.388889e-19 kWh |
| 1000 fJ | 2.777778e-19 kWh |
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How the formula works
Both femtojoule and kilowatt-hour measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in femtojoules by 2.777777778e-22 to get kilowatt hours. To reverse the conversion, multiply a kilowatt-hour value by 3.600000000e+21 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 Kilowatt-hour (kWh)?
A kilowatt-hour (kWh) is the standard billing unit for electricity, equal to 1,000 watts sustained for one hour.
How do I convert femtojoules to kilowatt hours?
Multiply the femtojoule value by 2.777777778e-22 to get the equivalent in kilowatt hours. For example, 5 fJ × 2.777777778e-22 = 1.388889e-21 kWh.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 2.777777778e-22 is an exact, non-rounded value.
Can I convert kilowatt hours back to femtojoules?
Yes. Divide the kilowatt-hour value by 2.777777778e-22, or multiply it by 3.600000000e+21, to get femtojoules.
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About converting femtojoules to kilowatt hours
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 kilowatt-hour (kWh) is the standard billing unit for electricity, equal to 1,000 watts sustained for one hour.
Use this calculator to move between femtojoules and kilowatt hours accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.