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One or Two Spaces After a Period?

Which is correct? Does it matter? The Crits investigate.

Believe it or not, the debate about whether you should put one space or two after the punctuation (period, question mark, or exclamation point) at the end of a sentence still rages on. A quick Google search yields a plethora of pages about it. Some folks are quite vehement and verbal about their viewpoints, too. So, what is the big deal and what should you, as a designer or an author, do about it?

There are many references online about the history behind the arguments, so I won’t waste space repeating all of that in detail. Instead, as I navigate this topical minefield, I will link to and list some of the pertinent information to leave as an exercise for you, dear reader, should you want to dig deeper.

One space

A great many grammar and typography professionals, as well as style guide manuals, these days are adamant that one should use only a single space between sentences. Some examples include the following:

Even looking at the way books about grammar and writing are printed during the 20th century and thereafter reveals that a single space between sentences is quite a predominant style. Most writing on the web also uses a single space. However, since the Hypertext Markup Language (HTML) specification reduces multiple instances of white space into a single one, the spacing using in online documents may not be as compelling an argument.

Two spaces

Many people use two spaces because they were taught to do so in typing class, because they perceive it as looking better, or to emulate the wider gap between sentences that appeared in earlier examples of typeset literature.

In fact, many style guides and typesetting manuals, including those before the invention of the typewriter, detailed extensive rules about how much space to use between letters, words and sentences. Often, the space between sentences was defined to be wider than the space between words, as documented by the following sources (thanks to blogger heraclitus for these links):

Even the Chicago Manual of Style, circa 1906, dictated that the space between sentences should be an em-quad (the width of the letter “em”). It remained that way until 1937, when an en-quad (the width of the letter “en”) became the recommended inter-sentence spacing. Finally, by the eleventh edition in 1949, there was no longer a difference between inter-word and inter-sentence spacing.

Space vs. space

Although I learned to type on a manual typewriter long, long ago, I have no recollection of using two spaces between sentences. Perhaps I did do it. However, I quickly moved to writing on a computer (Atari Writer in the early 1980’s) followed by an early start in desktop publishing (Ventura Publisher in the late ’80s and QuarkXPress in the ’90s) where using two spaces wreaked havoc on layouts, especially when using justified alignment.

Regardless, a key factor in this debate that I do not see much coverage of is that the physical space between sentences is related to, but a completely different thing from, the number of space characters that exist between those sentences.

How much visible space separates sentences is distance. It is a matter of layout, a decision based on design and aesthetics. Documented studies about the impact of spacing on readability and comprehension are, as of yet, inconclusive. As a result, the amount of gap you use is open to interpretation and artistic taste. If a particular typeface or body of work lends itself to the use of more or less space, go for it.

On the other hand, whether you press the spacebar once or twice upon reaching the end of a sentence, and before starting another one, is a matter of training, preference, or both. Using many space characters does not necessarily result in a larger gap (as in the case of HTML). One could say that pressing the spacebar more than once wastes effort.

Others might say that using two space characters is helpful to indicate the end of a sentence as compared to the end of an abbreviation and, thus, enables publishers to automatically apply the desired amount of separation. Although this sounds logical, in reality, none, one or more space characters could appear after any punctuation. Ultimately, the person tasked with laying out the page has to deal with too many or too few space characters, unless they are working with a writer who is a very accurate and conscientious typist.

The verdict

So, you have read this far and, as a writer, are still wondering how many times you should hit the spacebar between sentences. If you are the sole author, editor and publisher of the content, you probably have free reign to use as many space characters as you like. Proceed to your heart’s content.

If you are working with someone who will be laying out your manuscript, find out if one convention or the other is required or would be more productive to the publishing workflow. If it does not matter, do what you are comfortable with.

If you are writing with others, it may be beneficial for everyone to agree to use the same convention, unless all extra spaces will be automatically reduced or otherwise normalized by some other means. Otherwise, inconsistent spacing could prove annoying for everyone involved.

Perhaps someday, publishing software will leverage linguistic processing to automatically determine where one sentence ends and the next one begins. Then the amount of space, the expanse, can be truly independent of space, the character.

(Featured image credit: NASA/C. Reed)


Tell us what you're thinking. Leave a comment.

  1. Tim Musgrove says: December 13, 2013


    While I would admit that the overall trend is toward just using a single space, I dare say you’ve overlooked a couple of things that make the case appear more lopsided than it really is.

    For starters, you give the impression that authoritative sources have not been recommending the use of extra spacing for many, many years. But here’s a source from 1996 that specifies (on p. 24) that typesetters should use the equivalent of 1.5 character spaces between sentences:

    Also you are not considering whether practices might be different in academia and/or in the UK as opposed to mainstream American publications. Having earned a PhD in a program that carried a lot of UK professors, I have to say, anecdotally of course, that the double-spacing was more prevalent in these circles than it is in general usage.

    A rather tricky aspect of this is the difference between what typesetters tell authors to submit to them, as opposed to what those same typesetters then do in the actual typesetting. Some of their typesetting systems, like TeX, can automatically adjust kerning after terminal punctuation, and this reduces the need for authors to do it themselves — they needn’t “waste” that extra keystroke, knowing that the software will implement the magical 1.5 character spacing for them. This auto-space-expansion inherent in the TeX typesetting system is especially used by academic publications today.

    But when one doesn’t have that system available, and one still wants a bit of extra space between sentences, the only way to emulate it is to manually type two spaces, rather than one. This is also overlooked by your analysis — that two spaces can be a writer’s “best fit” attempt to reach the typesetter’s ideal of 1.5 spaces.

    Finally, you don’t look at the historical context of *why* publishers in America started to go to one space in the first half of the 20th century. This is around the time of the two World Wars and the Great Depression when it is known that publishers faced paper shortages and economic pressures and started using thinner paper, smaller fonts, narrower margins — anything to reduce the number of pages needed to get a book into print. If sentences average 60 characters, then reducing to one space at the end saves about 1.5% of the amount of paper. This is the context of the change and the motivation of it, meaning it was not out of some authoritative decree as to what is inherently preferable.

    Putting this all together, its far more reasonable and defensible to use two spaces than what your synopsis would suggest.

    Timothy A. Musgrove, PhD.
    San Jose, CA

    • Peter says: December 14, 2013

      @Tim: There are many examples, indeed, on both sides of the argument, several of which you’ve thoughtfully included. In the end, the characters used in a manuscript versus how they are represented on the page (whether physical or electronic) are issues that may or may not be interdependent. The former is an issue of composition standards and writers often must conform to what a particular publisher requires. The latter is a matter of style and, depending on the technology being used, may result in more or less space regardless of how many the writer entered. Thus, I stand by my pragmatic verdict that, regardless of what anyone thinks is the “right way”, the use of one or more spaces between sentences depends on who you must interact with (co-writers, editors, publishers, or no one at all) and the requirements agreed upon by the parties involved.

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