From this Slate article:

Hundreds of years ago some typesetters would end sentences with a double space, others would use a single space, and a few renegades would use three or four spaces. Inconsistency reigned in all facets of written communication; there were few conventions regarding spelling, punctuation, character design, and ways to add emphasis to type.


Every modern typographer agrees on the one-space rule. It's one of the canonical rules of the profession, in the same way that waiters know that the salad fork goes to the left of the dinner fork and fashion designers know to put men's shirt buttons on the right and women's on the left. Every major style guide—including the Modern Language Association Style Manual and the Chicago Manual of Style—prescribes a single space after a period. (The Publications Manual of the American Psychological Association, used widely in the social sciences, allows for two spaces in draft manuscripts but recommends one space in published work.) Most ordinary people would know the one-space rule, too, if it weren't for a quirk of history.

However, a double-space after period rule is still the default in some software, and most famously in TeX. This implies that the transition may not be as “complete” as the Slate article implies. So, my question is: can we somehow date the end of the double-space?

  • 6
    This question on English section of StackExchange might be helpful: How many spaces should come after a period/full stop?
    – Hrulga
    Nov 25, 2012 at 19:21
  • 3
    Some of the absolutes about the "one space rule" are not as absolute as you - and many - think. The practice of additional spacing after a paragraph is not something that originated with the typewriter, it dates back a long time before that. Single spacing as a "rule" is relatively modern. Moreover there is an important distinction between double spacing by pressing space twice, or additional spacing that is added during typesetting when a space appears after the end of a sentence - many don't consider the two as distinct. The link in the above comment is a good start. Nov 26, 2012 at 2:21
  • 1
    The article on TeX explains quite clearly that it's not that simple: The space may be wider, but it's not double spaced. Nov 26, 2012 at 7:36
  • The question might be more accurately written "Can the end of wider spacing after sentences be dated". Historically, the norm was not "two spaces after a period", but rather one extra-wide space after the end of a sentence.
    – supercat
    Jun 16, 2014 at 18:56
  • possible duplicate of Double space acceptable after period before abbreviated title?
    – Scott
    Jun 12, 2015 at 20:25

2 Answers 2


If you have an account at the AP Style Guide you'll see that this process is already in the works.

It's part of AP style to not put 2 spaces after a period.


  • Link doesn't work for me...apparently you need an account?
    – Brendan
    Dec 14, 2012 at 16:07
  • See the first line of my reply, "If you have an account at the AP Style Guide you'll see that this process is already in the works." Jan 2, 2013 at 23:23

Historical typesetting practice put more space after a sentence-ending period than between words or after abbreviations. Typewriters didn't offer variable width spaces, but putting two spaces after a period left an amount of space that was roughly comparable to typesetting practice.

The change in typographic practice is directly attributable to the rise of automated typesetting equipment which was unable to handle the larger spaces properly. The lack of a widespread revolt when newspapers eliminated the extra space after sentence-ending periods subsequently allowed that style to become "accepted". Publishers didn't mind the change, since using a wider spaces after sentence-ending punctuation requires that the typesetter accurately recognize which punctuation is supposed to end sentences; making all spaces the same width avoids the possibility that a typesetter might get it wrong.

Personally, I think it's unfortunate that typographical laziness has prevailed, especially given that computers would be have no trouble handling sentence spacing properly when two spaces are used after punctuation, but cannot be completely accurate otherwise unless given explicit instruction. Since it's much easier for an author to simply hit the spacebar twice after sentence-ending punctuation than to figure out when a computer might otherwise get confused and add the appropriate overrides, the elimination of the extra spaces increases the likelihood of typographical mistakes with documents set according to traditional spacing practices.

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