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.
Millijoules to Kilowatt hours
Convert Millijoule (mJ) to Kilowatt-hour (kWh) instantly with an exact formula, conversion table, and FAQ.
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Convert millijoules (mJ) 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 = mJ × 2.777777778e-10
Results update instantly for Millijoules to Kilowatt hours conversions.
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Formula
kWh = mJ × 2.777777778e-10
mJ = kWh × 3600000000
Conversion table
| 1 mJ | 2.777778e-10 kWh |
| 5 mJ | 1.388889e-09 kWh |
| 10 mJ | 2.777778e-09 kWh |
| 20 mJ | 5.555556e-09 kWh |
| 50 mJ | 1.388889e-08 kWh |
| 100 mJ | 2.777778e-08 kWh |
| 500 mJ | 1.388889e-07 kWh |
| 1000 mJ | 2.777778e-07 kWh |
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How the formula works
Both millijoule and kilowatt-hour measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in millijoules by 2.777777778e-10 to get kilowatt hours. To reverse the conversion, multiply a kilowatt-hour value by 3600000000 to get back to millijoules.
Frequently asked questions
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.
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 millijoules to kilowatt hours?
Multiply the millijoule value by 2.777777778e-10 to get the equivalent in kilowatt hours. For example, 5 mJ × 2.777777778e-10 = 1.388889e-09 kWh.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 2.777777778e-10 is an exact, non-rounded value.
Can I convert kilowatt hours back to millijoules?
Yes. Divide the kilowatt-hour value by 2.777777778e-10, or multiply it by 3600000000, to get millijoules.
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About converting millijoules to kilowatt hours
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. 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 millijoules 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.