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One Space Or Two Spaces?

When I began writing technical documentation and courseware for Guru Labs, I asked a question during training about whether we should be putting two spaces after a period, colon, question mark and exclamation point, or one. The answer shocked me, as I was hoping for the standard answer as a means of teaching the rest of my colleagues. The answer was ONE space, not two. Then, I listened to the argument.

When the first commercially successful typewriter was invented by Christopher Latham Scholes in 1867 and sold to Remmington, each letter on the typebars were the same width. This is known today as a monospace font. Initially, rumor has it, that typists only put one space after the end of a sentence, question, or exclamation. However, in the early 1920s, we began to see additional spaces added, sometimes more than one, at the end of these punctuations. The "unwritten rule" was that two spaces were all that was needed, no more, and thus became the standard practice for published works.

This practice continued well into the age of computers, and was even taught in typing class (I was taught it too). However, computers have an advantage over typewriters- variable width font. In other words, the width of the letter "m" is different than the width for the letter "i". Due to these proportional fonts, we no longer need that extra space. In fact, we could easily say that the standard practice of putting extra spaces in our text is down right dead. Here are some reasons why you do not want an extra space:

  1. It is inefficient, requiring an extra keystroke for every sentence.
  2. Even if a program is set to automatically put an extra space after a period, such automation is never foolproof.
  3. There is no proof that an extra space actually improves readability.
  4. Two spaces are harder to control for than one in electronic documents.
  5. Two spaces can cause problems with line breaks in certain programs.

As an interesting side note, if you are an HTML developer, you must explicitly use the escape sequence for two spaces "  ", as HTML will ignore the extra space, and only place one in the rendered text.

Spend some time online Googling whether to use one space or two following sentences, and you will quickly see that the trend has reversed back to using a single space, not two. In the meeting with my coworkers, I was quickly humbled, and have since been using one space at the end of my fullstops instead of two. It was an easy habit to get into, and you should be doing the same.

{ 13 } Comments

  1. Lee | December 7, 2008 at 8:04 am | Permalink

    And most importantly, two spaces is visual layout, not semantic information. If a browser or PDF renderer decides to insert an extra space for typographic reasons due to the font in use, that might be fair enough (but probably isn't). But if you EVER put that into a document, you're probably using a horrible, outdated workflow. This is also why your browser is right to ignore you when you insert extra whitespace.

  2. Paul Kishimoto | December 7, 2008 at 8:43 am | Permalink

    (via Planet Ubuntu) If you use TeX or its derivatives, you will note that it puts a wider space after a full stop. The exact width seems to vary from document to document and package to package.

    I'm not sure what Lee meant by "probably isn't [fair]," but I really like this approach:

    This sidesteps your reasons 1, 4 and 5; heuristics do a decent job of addressing reason 2. As for #3, readability is one of those subjective issues on which one can never have conclusive proof one way or the other. But even with TeX, the lesson is the same: one should never actually *type* a second space.

  3. Miles | December 7, 2008 at 10:12 am | Permalink

    Nerver heard of this two-spaces thing. My only advise would be to check out if you actually need a regular space, or an unbreakable one.

  4. Me | December 7, 2008 at 12:35 pm | Permalink

    This problem only arises for WYSIWYG editor users. In LaTeX the number of spaces is irrelevant. Only the existance of spaces is important to seperate the words and dots, commas etc. The rest is done by the typesetting engine.

    [WORDPRESS HASHCASH] The poster sent us '0 which is not a hashcash value.

  5. rawsausage | December 7, 2008 at 1:05 pm | Permalink

    If (la)tex does not do it, it is probably wrong.

    [WORDPRESS HASHCASH] The poster sent us '0 which is not a hashcash value.

  6. Robin | December 7, 2008 at 2:04 pm | Permalink

    The two-spaces thing makes sense for readability. It gives a visual break a the end of sentences. However, as Lee says, if you have to do it yourself, you're doing it wrong. Your typesetting system should do it for you if needed. I know LaTeX does (well, I doubt it uses two spaces, but it does allow a bit more space at sentence ends), I don' t know about others.

    P.S: If your blog comment form is OpenID enabled, why do I still have to enter the other details?
    P.P.S: If you put an OpenID URL into the website box, and then sign in using it, you get an error message saying you must use the comment form to submit comments. I suspect you have an anti-spam measure that isn't understood by your OpenID mechanism.

  7. Aaron | December 7, 2008 at 8:54 pm | Permalink

    I'll look into the OpenID bugs on my blog. Thanks.

  8. Robin | December 7, 2008 at 2:05 pm | Permalink

    P.P.P.S: The URL I gave it isn't an OpenID one, yet it claims that it is. I think your setup there might be a bit buggy.

  9. Michael "Typist" H. | December 7, 2008 at 5:00 pm | Permalink

    Personally, I've never heard of the controversy of one-space vs. two-space. I'm afraid that I've always used one space, and have never heard of the concept of using two. Of course, if the font want's to put more space at the end of spaces, then it's perfectly okay.

  10. Floris | December 8, 2008 at 1:22 am | Permalink

    I believe that before the introduction of the typewriter, a special spacing, somewhere between 2 and 3 normal spaces in size, was used in-between sentences. However, on the typewriter there was no room for this special space and for that reason people used 2 spaces as a workaround. If you ask me, it is still a good idea to use 2 spaces, as a workaround. But of course it is better to use that special space.

  11. Matthew East | December 8, 2008 at 5:09 am | Permalink

    I also like using a single space between sentences. However, double spaces is extremely commonly used in the UK as well. In my company's Style Guide, double spaces are recommended. That annoys me, especially because of the mayhem that it creates in Microsoft Word's justification feature.

    A balanced article setting out the various points of view can be found here -

  12. sjz | December 8, 2008 at 7:30 am | Permalink

    There are other examples of practices that typists adopted to compensate for the shortcomings of typewriters (as compared to human typesetting) that have, over time, petrified into rules that now get passed on without thought. You'll find these in author requirements for magaziines and journals, in-house company guidelines for document preparation, and in requirements that teachers impose on your children's submitted homework.

    Off the top of my head:

    1) Double-spacing. Single spacing on many typewriters led to much denser packing of lines than any human typesetter would permit. Hence double-spacing by typists. This became such a norm that even when typewriters allowed line-and-half spacing, its use was limited. It's particularly sad, now that word processors can easily do proper variable line spacing, to see people struggling to force their WP to use fixed height double spacing just because some editor or teacher believes this is how it should be done.

    2) Blank lines between paragraphs. Originally another way to compensate for the inability to do flexible line spacing on a typewriter. Now, there's no denying that a typesetter will try to add vertical space between paragraphs, but I still find that many people believe they actually have to leave a blank line between paragraphs in their word processed documents to get this effect.

    3) Underlining was commonly used to indicate text that, when typeset, would have been italicized. You will still see occasional guidelines to underline titles in bibliographic listings because the common typesetting convention was to italicize these, but typists had to underline, and eventually someone wrote out the underlining as the "rule" to follow. (Even more common is the practice of putting titles in quotes, another convention that arose largely because people could not type in italics.)

  13. Seth | December 9, 2008 at 1:24 am | Permalink

    From The Elements of Typographic Style by Robert Bringhurst:

    2.1.4 Use a single word space between sentences.

    In the nineteenth century, which was a dark and inflationary age in typography and type design, many compositors were encouraged to stuff extra space between sentences. Generations of twentieth-century typists were then taught to do the same, by hitting the spacebar twice after every period. Your typing as well as your typesetting will benefit from unlearning this quaint Victorian habit. As a general rule, no more than a single space is required after a period, a colon or any other mark of punctuation. Larger spaces (e.g., en spaces) are themselves punctuation.