One Space or Two?

[Updated January 12, 2015, to integrate what had previously been bracketed updates.]

In A Manual of Style for Contract Drafting 12.21, I recommend that you use only one space, rather than two, after punctuation, whether it separates two sentences (periods, question marks, exclamation marks) or parts of a sentence (colons).

I’m hardly alone in this. The Chicago Manual of Style 2.12 (15th ed. 2003) says “A single character space, not two spaces, should be left after periods at the ends of sentences (both in manuscript and in final, published form) and after colons.” To my mind, that settles it, but I’ll note that The Associated Press Stylebook (2004) also calls for one space. So does Bill Walsh’s Lapsing into a Comma (2000). I could list others.

Nevertheless, even after rooting around online I remained uncertain what prompted use of two spaces and what prompts calls for use of one space. I found a helpful discussion of the issue in James Felici, The Complete Manual of Typography (2003). Here is what Mr. Felici has to say about “word spaces,” which he defines as blank characters created by pressing the spacebar on a keyboard:

Typewriter spaces have the attraction of always being the same size, so it was natural to use them in multiples for paragraph indents or gaps in a typewritten line. You could align things by adding word spaces before them.

Spaces in word processors and typesetting programs, though, have no fixed width, so they can’t be used in this role. Not only do the widths of word spaces (or space bands) vary from typeface to typeface, but they are also flexed—made wider or narrower—as lines of text are fit into a given line length, or measure. In fact, dedicated typesetting systems routinely ignored multiple word spaces, collapsing them into a single space, because consecutive spaces have no role in typesetting. Multiple word spaces were assumed to be a mistake.

Nevertheless, the habit of aligning text by using series of word spaces has persisted, mainly because word processing programs (and the desktop publishing programs based on word processing precedents) allow it. Indents should ideally be created with a program’s indentation commands or, less desirably, with the Tab key. Gaps in text should be created with a series of fixed spaces, such as em and en spaces, whose widths are constant unless the size of the type changes.

The typewriter tradition of separating sentences with two word spaces after a period has no place in typesetting. The custom began because the characters of monospaced typefaces used on typewriters were so wide and so open that a single word space—one the same width as a character, including the period—was not wide enough to create a sufficient space between sentences. Proportionately spaced fonts, though, contain word spaces specifically designed to play the sentence-separating role perfectly. Because of this, a double word space at the end of a sentence creates an obvious hole in the line.

In this 2011 Slate article urging people to stop using two spaces, Farhad Manjoo cites Felici. On the other hand, others are of the view that use of two spaces after a period can’t be attributed to the typewriter. Robert Bringhurst, The Elements of Typographic Style 28 (3d ed. 2004), regards it as a matter of typography fashion, calling it “this quaint Victorian habit.” For extensive analyses suggesting that use of two spaces has long been part of typographic design, see Dave Bricker’s blog post on the subject, here, and one on Hericlitean River, here.

Ultimately, though, the history of two spaces is less important than what we do with it now. As the online Chicago Style Q&A states, there’s no evidence that using two spaces makes text easier to read. Consequently, the only conceivable defense of the practice is that it’s harmless. But as also noted in the Chicago Style Q&A, using two spaces is inefficient, requiring an extra keystroke for every sentence, and is harder to control, in that any document created using the two-space rule is likely to contain a “a smattering of instances of both three spaces and one space after a period, and two spaces in the middle of sentences.”

But perhaps the deciding factor should be that all authorities recommend using one space. Consistency in typographic practice is a good thing, so join the herd and switch to one space.

Nevertheless, discussion persists. Frank Romano, professor emeritus of the School of Print Media at the Rochester Institute of Technology, told me that it comes up almost weekly, presumably to his chagrin. Of course, law firms and most lawyers are wedded to two spaces. It would be a mistake to assume that this is the result of a reasoned decision. Instead, you can attribute it to the same oblivious conservatism that has caused them to perpetuate any number of other deficient usages.


So if you’re still using two spaces, stop it—your credibility is at stake!

(This post was written from the U.S. perspective. I’d be interested to hear how this issue—if it is an issue—plays out in other countries.)

About the author

Ken Adams is the leading authority on how to say clearly whatever you want to say in a contract. He’s author of A Manual of Style for Contract Drafting, and he offers online and in-person training around the world. He’s also chief content officer of LegalSifter, Inc., a company that combines artificial intelligence and expertise to assist with review of contracts.

31 thoughts on “One Space or Two?”

  1. I’ve gone back and forth. I was a proponent of the single space after sentence for the longest time. However, what I’ve since realized is that sometimes using a single space after periods can be confusing when you have abbreviations like Dr., Ms., or St. and at times downright ambiguous. Using a double space is a commonly understood usage for “hi, I’m in a new sentence regardless of what you think that period was for.”

    Also, the argument that spacing is typographically fixed by modern word-processors so that there is sufficient space after the end of a sentence goes to hell when you’ve got a justified document (and there are those out there).

  2. Mike: I elected not to weigh down my post with it, but you’re correct to raise the issue of periods within a sentence.

    I don’t think “Mr.” and “Dr.” could pose a problem. Where there could be confusion is when a sentence ends with an initialism, with the letters separated by periods, and the next word could be considered to be a continuation of that sentence rather than the beginning of a new one. An example: “The measure has been controversial in the U.S. States that have considered adopting it are few and far between.”

    But such occurrences are infrequent enough that I’m unwilling to lumber myself with two spaces as a prophylactic measure. And I doubt that two spaces would solve the problem; Frank Romano, whom I cite in my post, agrees with me.

    I was delighted to give up two spaces and, unlike you, I’ve never contemplated going back.

    As for using two spaces AND full justification ….


  3. Ken,

    I really don’t understand why this issue persists. While a high school student in the late 60s I worked in a print shop and the rule then was two spaces after a sentence in monospaced fonts and one space in proportional fonts. What’s so hard about this rule?


    • In some cases, you may not know what typography may ultimately be used for a document you are typing, or it may possibly end up in more than one format. But, even if you are sure, I don’t see what’s so wrong with two spaces, and nothing in this article makes that clear to me. To the contrary, two spaces is likely to make sentences more distinct from each other, and seems better to me.

  4. Many, many years ago, in high school typing, I learned to place two spaces between sentences. Years later (but while offices still used typewriters) a typesetter friend told me that the two space rule was appropriate for mono-spaced type but that in typesetting, with proportional spaced fonts, she used one space between sentences.

    A few years later, in 1984, the MacIntosh was introduced with proportional spaced fonts and an emulation of the typesetting conventions . My friend suggested that users of the Mac should only use one space between sentences. Robin Williams (a graphic designer), in her 1990 book "The Mac is Not a Typewriter", also also taught the use of one space.

    Now the Windows based PC also follows typesetting conventions and uses proportional spaced fonts. Typewriter like mono-spaced faces are a thing of the past and rarely seen in any office or profession. The two space rule should die with the typewriter.

  5. Your quote says, “The typewriter tradition of separating sentences with two word spaces after a period has no place in typesetting.” In the strict sense, I do not consider the composition of an office original to be typesetting–as compared to the use of the computer for desktop publishing.

    I use two spaces after the period ending a senetence, for the same reason that I use flush left justification. I want to avoid any suggestion that this is typeset material.

    I believe it is pretentions to attempt to replicate typeset formatting in one-off business documents. The mere fact that you have the capability does not justify the use.

  6. John: Whereas you may not consider word processing to be typesetting, typography professionals would disagree with you. For instance, “The Complete Manual of Typography” (page 79) says that “every computer user now uses text-processing programs that should properly follow the rules of typesetting, not typing.”

    Note that “rules of typesetting” doesn’t refer to some arcane body of knowledge; instead, it’s simply the alternative to what one might call “rules of typewriting.”

    Incidentally, following the rules of typography doesn’t require full justification. It’s just one of various options, a ragged right margin being another. At some point I’ll do a post about justification.


  7. Otto: No publisher, including publishers of newspapers, ever used two spaces. But I feel your pain: your complaint is similar to the issue discussed in Mike's comment and my response. I don't think there's any quick fix. Maybe a new set of glasses! Ken

  8. I wish newspapers would go back to two spaces between sentences. With only one space it is relatively easy for a fast reader to confuse a period with a comma. Then if the next sentence starts with a proper name that would be capitalized anyway, one’s eye can easily run the stop sign. It isn’t until the reader is totally confused that the realization dawns that maybe a period was missed along the route and back-tracking is necessary to make sense of the passage Am I the only one this happens to?

  9. One problem I’ve run in to is ending sentences with “a.m.” or “p.m.” I now just avoid this (not too hard), but it is visually confusing when only using one space between sentences.

    Although the style guides vary, the proper typographical solution is to use small caps for this kind of abbreviation. But my legal writing prof specifically said not to do this. Small caps are kind of a pain anyway. Despite the advice of every style guide (The Red Book, MLA, Chicago), he also prefers two spaces between sentences although does not require it.

    I personally type two spaces after a period by force of habit, and likely always will. In email it makes sense: you should not assume a proportional font on the other end. (And in email you should stick to strict ASCII and avoid any special formatting, but that’s a different story.)

    When creating something that is to be printed or turned into a PDF (same thing really) I always do a search and replace on the two spaces.

    I recommend the book “The Mac is Not a Typewriter” (there’s also “The PC is Not a Typewriter”). It is a crash course on the basic typographical conventions one should follow when creating text on a computer.

  10. To convince those old-fashioned lawyers to give up their old-fashioned ways (using French spacing and omitting serial commas), it might be useful to have them review Supreme Court rulings, or Federal legislation, or briefs filed by the U.S. Solicitor General: they don’t use French spacing and they do use serial commas.

    Unfortunately, all of those mentioned above do use “Table of Contents” as the heading for a table of contents, but that’s a very common error in many occupations.

  11. In my company, we have talked about using two spaces for left-justified text but one space for fully justified text. Do you think justification should play a role in whether to use one space or two?

  12. Heidi: I can think of three reasons not to adopt the convention you suggest. First, fully justifying text is a bad idea, as it makes it harder to read. (I’ll be writing about this at some point.) Second, if you nevertheless switch between left justification and full justification, you’d have to adjust the spacing after punctuation; that would be a tremendous nuisance. And third, typographer’s aversion to two spaces bears no relation to how the text is justified. Ken

  13. I learned to type on a manual typewriter, in the 1960’s. Of course we “thump-thumped” at the end of every sentence. I usually do, to this day. I am trying to stop, but I find the finished product more difficult to read. In a long piece, therefore, especially something written for an older judge, I leave lots of white space. Thump-thump.

  14. Geographical feedback: I was surprised by this discussion (came here from the post about justified vs. ragged right), in my area (I think “ex-USSR” and “Eastern Europe” are the closest descriptions) there is no such issue. One space after a period, and it would never occur to me to use two spaces instead.

    Final thoughts – the blog is interesting, I’m positively impressed by the fact that such issues are discussed by “law people”.

  15. It’s 5 a.m.  I am going to sleep.

    It’s 5 a.m. and I am going to sleep.

    This is why I have always used two spaces after a “.” and always will until word processors become smart enough to recognize and specially handle the end of a sentence.

    I wonder—does a professionally typeset document really use the same space after a period in a sentence as it does between two sentences?

  16. Mike: Professional typographers don’t see any benefit to using in a word-processing document two spaces between every sentence in an uncertain attempt to address the issue you raise. I agree with them.

    As for your question, I’m not qualified to answer with any certainty.


  17. I became a convert to ragged right a number of years ago, but I continue to use two spaces after a period. Why? So that the skimming reader, in search of a specific thought, point, etc., can more readily jump from sentence to sentence.

  18. I've seen the counterargument about periods within a sentence. However, just like any issue with a sentence that might impair comprehension or readability, these instances should simply be rewritten. There are plenty of precedents for this. It's much easier to rewrite the infrequent issues that might be confusing – as opposed to changing punctuation and typography rules across the board for a language. The holistic change would also impact readability. For more information on that, see the below Wikipedia article.

  19. I'm only 29, so it'd be tough to make the argument that I'm "from the old school". Yet, throughout elementary and high school I was always taught to use two spaces at the end of every sentence. That basic rule was never really questioned, at all… by anyone.

    In fact, I only realized that this standard had changed when I was reviewing some of my fiance's writing a few months ago. She heard the classic "thump thump" and asked what I was doing. I told her that she had accidentally left only one space between her sentences. A debate ensued over the proper way to separate sentences, and I was rather startled to find that most authorities on the matter agreed with her "one-space" argument.

    Nonetheless, I will probably continue using two spaces at the end of a sentence until the day I die. It's not so much a matter of choice… I just do it unconsciously these days. It's literally so ingrained in my process of typing that to stop now would be more trouble than it's really worth. Ultimately, I don't hold any strong views as to whether or not two spaces or one space ought to be used. It really doesn't matter all that much, and seems to me to be quite trivial. Thus, it makes little difference to me that I use two spaces between sentences instead of the single space dictated by pesky rule-makers with way too much time on their hands.

  20. To Mike and Ken:
    Typesetting programs (I use Latex for scientific manuscripts) usually create a elongated space after a period. If this must be avoided (eg, after a.m.), a special character is required to suppress this function. It's extra work, but creates reliable and pleasant output.

  21. I would prefer to keep the double spaces. The software rendering the text should decide for itself the best way to handle it. If you fail to put the spaces in, the information is lost, and the renderer can no longer display the text correctly in a monospaced font. Note that Neil's triple-space revolt above was thwarted, at least in my browser.

  22. Umm, obviously no one here has ever looked at a book published before about 1930. The STANDARD almost everywhere from the 1700 until the early 1900s was a much larger space after a period. This tradition had nothing to do with typewriters — it was simply the accepted way of signaling the larger break in the text after a sentence. For a number of reasons, that changed in the mid-1900s, but style guides in the 1800s pretty consistently call for the larger spaces. Statements like “no publisher ever used two spaces” is ridiculous, as anyone can see by pulling a book off of a shelf published before 1900, and in English-speaking countries, the larger spaces continued at some publishers until the 1940s and even 1950s.

    Fads in typography have changed, but that doesn’t mean things have always been that way.

  23. Ken, you’re almost certainly right, but my father sent me for typing lessons at a secretarial college in Glasgow at the age of 16, and I was taught to double-space. Old habits die hard. I have probably seen single spacing more in US text than in UK text.

  24. What I miss from two spaces following a period is that you could easily advance through a document for proofreading purposes one sentence at a time by using the search feature for the period and double space. This avoided unnecessary stops at myriad other locations. I’ve not yet found a satisfactory substitute; is there one?


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