In the ever challenging pursuit of simplifying visuals for Users, an issue came up while web developing.

It is a relative simple issue: I want to offer Users a selection for weekdays using only one character per weekday name.

Would M T W T F S S be confusing?

  • Not to me - at least not if they were all visible and the context was logical
    – mplungjan
    Commented Feb 4, 2014 at 13:16
  • You might like to look at page 24 oof this guide, which shows how short-form "Day Applicability" codes are used in the UK bus industry for timetabling, etc. Buried somewhere in my decades-old personal C++ library I have a subroutine that takes as input a single byte where each of bits 0 -> 6 are either on or off, to indicate that something either does or doesn't operate Mon -> Sun. It returns an unambiguous string of 5 characters or less for any combination. Commented Feb 4, 2014 at 15:06
  • I have seen cases where clerical staff use H for Thursday, and $ for Sunday, but the general public particularly don't like the first of those two, so they aren't in general use. Commented Feb 4, 2014 at 15:08
  • Microsoft Windows even offers a localized version of this, LOCALE_SSHORTESTDAYNAME
    – MSalters
    Commented Feb 5, 2014 at 11:45
  • 1
    I know its not what he was asking, but maybe can be usefull for internationalization purpose: In spanish we follow the convention. LMXJVSD In my current project we will have to translate this convention to several languages and I will added it, just in case someone might be interested in some other languages ^^ Commented Aug 4, 2014 at 8:32

3 Answers 3


Is there a single-character convention for the weekdays?

Yes, pretty much all dialects of English recognise the initials of the week-days.

Two- and three-letter abbreviations are also common. To use Su M Tu W Th F Sa to differentiate those days with the same initial, or just S M Tu W Th F S which does the same but doesn't worry about the weekend days, is rare but not unheard of.

Would M T W T F S S be confusing?

No. Nor would S M T W T F S. This latter is more common in English-speaking countries as a convention, if there's no need to stick to any of the standards that insist on Monday as the start of the week, and even if there is (that information can be overlaid on the more conventional layout if necessary).

Other permutations would be rarer though, S S M T W T F would be less easily read and T F S S M T W had better have a very good reason for being used.

There are places that use M T W R F S U but this is mostly when a one-character unambiguous letter is needed outside of a context that helps explain it, and to be strongly avoided in any other case.

If you may need to internationalise this UI though, you may find that other languages don't handle such heavy abbreviation as well. I'd at least allow room for Dé hAoine to become hA if other languages may need to be considered.


I would find it hard to think of any alternative for this, except in case of American style weeks, which would look like:


I may not be representative, but the sequence MTWTFSS immediately reminds me of weekdays as does JFMAMJJASOND brings to mind months of the year, so unless the context would throw me off, I would certainly not be confused by it.


I have also seen


where the "H" is as in THursday.

  • 6
    as in H orrible
    – mplungjan
    Commented Feb 4, 2014 at 13:25
  • 2
    @mplungjan: didn't say I liked it. Said I've seen it. Commented Feb 4, 2014 at 13:26
  • If there is a need for an H (presumable to distinguish Thursday from Tuesday), why isn't there a need to distinguish Saturday from Sunday?
    – bib
    Commented Feb 4, 2014 at 13:34
  • @mplungjan not as horrible as M T W R F S U is urrible, though in fairness that's only used in very specific contexts.
    – Jon Hanna
    Commented Feb 4, 2014 at 13:38
  • I'd already commented about H before seeing this. But I've never seen it used in contexts where Sunday isn't also switched to $. Commented Feb 4, 2014 at 15:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.