3, 2 and 1 letter abbreviations for days of the week


These are the ones I use, depending on how much space I have to work with. Generally, when I work with graph paper, I don’t have much space for the days of the week.



  • Mon
  • Tue
  • Wed
  • Thu
  • Fri
  • Sat
  • Sun


  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • Su


  • M
  • T
  • W
  • R
  • F
  • S
  • Y
  • commonly used by universities



  • M
  • T
  • W
  • T
  • F
  • S
  • S
  • where the position of the letter will tell you which day it is

One thing many foreign speakers find difficult is the difference between weekdays (Monday to Friday), days of the week (Monday to Sunday), as well as the fact that in Western Europe the week starts on Monday and not Sunday.

Does anyone have any other way of writing these?

Author: Janet Carr

Fashion, beauty and animal loving language consultant from South Africa living in Stockholm, Sweden.

5 thoughts

  1. The one day abbrevs shown are common as stated at colleges and universities (or at least used to be). They were first used to save precious space on 80-column IBM cards to show days of the week for class scheduling. This convention was carried over to newer systems. Students would register for classes by selecting the desired “course card”. Using 2 or more would have required double (14) or triple (21) the number of columns for a course that met every day (rare) that were otherwise needed for course titles, credits, instructor, etc. I’m surprised to see the “R” is not recognized by some since I thought this was quite common. I’ve seen both U and Y for Sunday.

  2. R for Thursday and Y for Sunday ? I’very never seen that before. It seems quite weird to me but why not. Once one got used to using abbreviations, they can be anything!
    I prefer using 2 or 3 letters as there is no confusion possible.

  3. My Pocket Filofax diary for 2016, week on one page, starts on Monday but I got a church diary for 2017, cut it up and punched holes, which starts on Sunday – which I prefer.
    Using R for Thursday and Y for Sunday is weird, I’ve never seen that before. I use a mixture of abbreviations:
    Sun, M, Tu, W, Th, F, Sat,

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