One Space or Two?

origin_2593463316In high school, when I learned to type, I was told that a period (or any punctuation) at the end of a sentence MUST be followed by exactly two spaces. Ten years later when I was writing curriculum units for publication I was told that a period (or any punctuation) at the end of a sentence MUST be followed by exactly one space. What happened?

The Abreviated Story:

First there were books…

Variable space typing has been part of printing for, well, basically forever. This meant that not all letters were the same width. A lower-case i didn’t take up as much space as a lower-case m, and making spaces of different sizes was easy. And at the end of a sentence a slightly longer space (though not as big as two spaces) was generally used.

Then came the typewriter…

origin_12149305295When most of us learned to type (or when our teachers learned to type) we learned on typewriters. Typerwriters are great, but they have an important limitation: every character has exactly the same width. Sentences look like this.  The i and the m were the same width. To add some extra clarity to the end of sentence, an extra space was added; so we all used two spaces.

Then came computers…

Then with affordable computers, the average person at home had access to variable space typing, letters and spaces of different widths; the computer took care of this automatically. Since then, the push for two spaces has been less common; many have gone back to one space. What do the style guides say now?

  • US Government Printing Office: One space between sentences.
  • Oxford Style Manual: One space between sentences.
  • Chicago Manual of Style: One space between sentences.
  • Modern Language Association (MLA): One space between sentences.
  • American Psychological Association (APA): Two spaces between sentences, for draft manuscripts. One space between sentences for published or final versions.
  • Style Manual for Political Science: One space between sentences.
  • Associated Press Stylebook: One space between sentences.

Oh, and now the Internet…

If you’re writing something that will end up on a webpage (like this blog post), it doesn’t matter what you do. HTML is programmed to ignore multiple spaces. No matter how many you put; one, two, three, four; it will be rendered as only one. Sorry. (That means in the “typewriter” text above I had to dig into the code to get the HTML to create a second space.)

What should we teach our students?

One space.


If you’re interested in longer versions of the history of sentence spacing you can find them here and here. For more specifics on what the style guides say about sentence spacing, that’s here.

photo credit 1: Cybjorg via photopin cc
photo credit 2: Marinw. via photopin cc

One thought on “One Space or Two?

  1. Yes! And while I try my darndest to teach “one space”, I fear there’s no hope for my own fingers, which still double-space after a period of their own accord. I am also reminded of the 1990 book, “The Mac Is Not A Typewriter”, which was where I first saw this history discussed.

    Oh! Wait- there’s a new chapter of this “one space or two” saga, too: the iPhone. On the iPhone, [space] [space] is shorthand for [period] [space]. They’re sort of threading the needle there: using the old way as a time-saving macro for the new way.

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