When you report Einstein units do you capitalize it? Since we're using it in the context of a unit (and not a name) is capitalization necessary?


The measured value was reported as 10 Einstein.


The measured value was reported as 10 einstein.

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    $\begingroup$ Unit symbols may or may not be capitalised, but unit names are never capitalised, as far as I know. $\endgroup$ Jan 7, 2017 at 17:05
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    $\begingroup$ It should be lowercase: N = newton, Pa = pascal, J = joule, for example, both of which are units derived from actual names. As a slight aside, the unit is highly redundant and non-recommended. I'd also suggest this was a better fit for physics.SE $\endgroup$
    – NotEvans.
    Jan 7, 2017 at 17:09
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    $\begingroup$ There is a question about this on English.SE. $\endgroup$
    – Marcel
    Jan 7, 2017 at 17:34
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    $\begingroup$ See also our recommendations concerning units on meta. $\endgroup$
    – user7951
    Jan 8, 2017 at 12:59

2 Answers 2


The non-SI unit einstein is not accepted for use with the SI and should be avoided.

Anyway, unit names are normally printed in upright type, and they are treated like ordinary nouns. Names of units are spelled with a lower-case initial in English, except in the beginning of a sentence when a capital initial is used. This also applies to unit names that are derived from a proper name of a person such as kelvin, newton, joule, pascal, watt, hertz, coulomb, volt, farad, ohm, siemens, weber, tesla, henry, and thus also einstein.

For SI units, it is only the unit name degree Celsius that contains a capital letter. In keeping with the rule, the unit degree begins with a lower-case d and the modifier Celsius begins with an upper-case C because it is a proper name.

However, in quantity names containing a person’s name, the person’s name is spelled with a capital initial, for example, the Einstein transition probability for spontaneous emission $A_{jk}$.

These writing rules are in accordance with following references:


From the ACS style guide (a reference book for conventions when publishing):

➤ Do not capitalize surnames that are used as units of measure:

ampere, angstrom, coulomb, curie, dalton, darcy, debye, einstein, erg, faraday, franklin, gauss, gilbert, gray, hartree, henry, hertz, joule, kelvin, langmuir, newton, ohm, pascal, poise, siemens, sievert, stokes, tesla, watt, weber.

Celsius and Fahrenheit are always capitalized. They are not themselves units; they are the names of temperature scales.


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