A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix.
Attojoules to Watt hours
Convert Attojoule (aJ) to Watt-hour (Wh) instantly with an exact formula, conversion table, and FAQ.
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Convert attojoules (aJ) to watt hours (Wh) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Wh = aJ × 2.777777778e-22
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Formula
Wh = aJ × 2.777777778e-22
aJ = Wh × 3.600000000e+21
Conversion table
| 1 aJ | 2.777778e-22 Wh |
| 5 aJ | 1.388889e-21 Wh |
| 10 aJ | 2.777778e-21 Wh |
| 20 aJ | 5.555556e-21 Wh |
| 50 aJ | 1.388889e-20 Wh |
| 100 aJ | 2.777778e-20 Wh |
| 500 aJ | 1.388889e-19 Wh |
| 1000 aJ | 2.777778e-19 Wh |
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How the formula works
Both attojoule and watt-hour measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in attojoules by 2.777777778e-22 to get watt hours. To reverse the conversion, multiply a watt-hour value by 3.600000000e+21 to get back to attojoules.
Frequently asked questions
What is Attojoule (aJ)?
A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix.
What is Watt-hour (Wh)?
A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
How do I convert attojoules to watt hours?
Multiply the attojoule value by 2.777777778e-22 to get the equivalent in watt hours. For example, 5 aJ × 2.777777778e-22 = 1.388889e-21 Wh.
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 watt hours back to attojoules?
Yes. Divide the watt-hour value by 2.777777778e-22, or multiply it by 3.600000000e+21, to get attojoules.
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About converting attojoules to watt hours
A attojoule (aJ) is a metric-prefixed unit of energy equal to 10-18 joules, a fraction of a single joule, using the SI atto prefix. A watt-hour (Wh) is the energy delivered by one watt of power sustained for one hour, equal to 3,600 joules.
Use this calculator to move between attojoules and watt hours accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.