Why are all the letters (A, B etc) and all the writings (Home, Page Up etc) on the keyboard, capitalized?


Especially, the letters, because a new user could rightly expect uppercase letters to be entered upon pressing those keys to find the contrary.

  • What would they press to make to make lowercase letters then? Feb 4, 2014 at 19:19
  • I don't understand how it that relevant to the question. Essentially my question is why is it printed F instead of f, Alt instead of alt etc? Feb 4, 2014 at 19:21
  • Just responding to the new user's expectation, which is why I made it a comment not an answer :) Feb 4, 2014 at 20:03
  • 1
    I think most of your question can be answered here: ux.stackexchange.com/questions/48636/…
    – mawcsco
    Feb 4, 2014 at 20:13
  • 1
    @Trevor This question seems to be about hardware keyboards.
    – André
    Feb 6, 2014 at 15:44

2 Answers 2

  • It's a rule in English language to capitalize captions, thus we have "Page Down" (or "Pg Dn") instead of "page down" - see http://libraryonline.com/?pID=48
  • Uppercase letters are easier to differentiate (especially I and L) that the lowercase ones
  • But the words on my Apple keyboard are all lower case ("enter", "caps lock", "delete"). I can also easily distinguish lowercase 'i' and 'l' without issue. Feb 4, 2014 at 19:30
  • 5
    In this particular case, I would rather say it's matter of visual design, which Apple puts a lot of focus into (and probably the result fits their style, also distinguishes them from the others), rather than usability. Feb 4, 2014 at 19:34
  • However, this has nothing to do with English. Letters were capitalized on typewriters, too. In all honesty, this was a long time before English was the world's first language.
    – yo'
    Feb 4, 2014 at 23:12
  • An Englishman Henry Mill was the first to patent the typewriter in 1714. Also, think of word "caption"; what I meant is capitalizing the first letters of expressions like "Page Down", not just single characters on the rest of the keyboard. The second reason is an answer why the single letters are capitalized as well. Feb 4, 2014 at 23:17

It's actually due to ISO 9995.

Depictions on the keytops
According to ISO/IEC 9995-1, the level is indicated by the row where the character is depicted on the keytop:
* Level 2 (“shifted”) above of Level 1 (“unshifted”)
* Level 3 (“AltGr”) below Level 1 (“unshifted”).

The group is indicated by the column on the keytop:
* The first or “primary group” at the left keytop border
* The second or “secondary group” at the right keytop border
Additional groups (if existing) in between.

When letters on a case pair are associated with a key, only the capital character need to be shown on the keytop for the primary group, while the lowercase character only is shown for the secondary group.

ISO/IEC 9995-3:2010 applied to the US keyboard layout ISO/IEC 9995-3:2010 applied to the US keyboard layout

  • While this is mostly correct (albeit the exact same answer as you posted on another related question), it doesn't cover why the keys such as Scroll Lock and Caps Lock are presented in capitalized Title Case. (Admittedly that is probably a harder reason to identify)
    – JonW
    Feb 6, 2014 at 12:15
  • 2
    Capitalizing the first character of each word gives a clear indicator as to the start of each word. Think PrtScn as opposed to prtscn, or PgDn and pgdn. It might not matter to an experienced user, but a less experienced user might appreciate that clarity. Single word keys then capitalize their first letter for consistency.
    – MildWolfie
    Feb 6, 2014 at 12:50
  • This answer has cause and effect inverted. ISO 9995 is the way that it is because, in 1994, it (largely) standardized an existing practice that had been around (even if one is only considering computer keyboards) for decades beforehand. So "It's because ISO 9995 says so." is circular, and doesn't provide a rationale for the the pre-existing design.
    – JdeBP
    Jan 2, 2016 at 10:21

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