A kilowatt-hour (kWh) is the standard billing unit for electricity, equal to 1,000 watts sustained for one hour.
Kilowatt hours to Femtojoules
Convert Kilowatt-hour (kWh) to Femtojoule (fJ) instantly with an exact formula, conversion table, and FAQ.
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Convert kilowatt hours (kWh) to femtojoules (fJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
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.
fJ = kWh × 3.600000000e+21
Results update instantly for Kilowatt hours to Femtojoules conversions.
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Formula
fJ = kWh × 3.600000000e+21
kWh = fJ × 2.777777778e-22
Conversion table
| 1 kWh | 3.600000e+21 fJ |
| 5 kWh | 1.800000e+22 fJ |
| 10 kWh | 3.600000e+22 fJ |
| 20 kWh | 7.200000e+22 fJ |
| 50 kWh | 1.800000e+23 fJ |
| 100 kWh | 3.600000e+23 fJ |
| 500 kWh | 1.800000e+24 fJ |
| 1000 kWh | 3.600000e+24 fJ |
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How the formula works
Both kilowatt-hour and femtojoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in kilowatt hours by 3.600000000e+21 to get femtojoules. To reverse the conversion, multiply a femtojoule value by 2.777777778e-22 to get back to kilowatt hours.
Frequently asked questions
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.
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.
How do I convert kilowatt hours to femtojoules?
Multiply the kilowatt-hour value by 3.600000000e+21 to get the equivalent in femtojoules. For example, 5 kWh × 3.600000000e+21 = 1.800000e+22 fJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 3.600000000e+21 is an exact, non-rounded value.
Can I convert femtojoules back to kilowatt hours?
Yes. Divide the femtojoule value by 3.600000000e+21, or multiply it by 2.777777778e-22, to get kilowatt hours.
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About converting kilowatt hours to femtojoules
A kilowatt-hour (kWh) is the standard billing unit for electricity, equal to 1,000 watts sustained for one hour. 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.
Use this calculator to move between kilowatt hours and femtojoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.