One space or two between sentences

Some people get quite passionate about how many spaces to put after a sentence-ending punctuation mark, but is there an absolute answer?

Other than the use of the serial comma, perhaps no other style guideline causes more contention among writers and editors as that of how many spaces to use after a period.

Several weeks ago, I wrote about 10 writing pet peeves. Among them was content written with two spaces after a period. I always use the find-and-replace feature to change two spaces to one in documents that I edit.

My insistence on one space after a period (or question mark or the dreaded exclamation point) touched off a barrage of comments from PR Daily readers. Many insisted that one space after a period is just a preference and that two spaces makes content easier to read. Others quoted style guides—such as the AP Stylebook—that clearly state: “Use a single space after a period at the end of a sentence.”

James Felici—author of The Complete Manual of Typography—calls this “the debate that refuses to die … In all my years of writing about type, it’s still the question I hear most often, and a search of the web will find threads galore on the subject.” (1)

XKCD has published a Web comic highlighting the spacing after a period controversy. Then there is the post, “Why two spaces after a period isn’t wrong (or, the lies typographers tell about history)” that disputes the conventional wisdom about spacing after periods. So which is it, one or two spaces? More important, why are we still debating this?

Many of us were taught to use double spacing between sentences when we took typing—on typewriters—in school. That’s the root of common belief that double spacing is correct, even when using word processing software. Some argue that the two-space habit is too hard to break, so why change?

One-space advocates claim the two-space rule was relevant only when using a typewriter, so the rule is now obsolete.

Both sides claim that readability and legibility are affected by the spacing after periods. Remember the “rivers of white space” we were told to watch out for in design class? Apparently they are more likely to occur when two spaces are inserted between sentences. However, studies on sentence spacing and reading effectiveness have been inconclusive. (2)

The AP Stylebook calls for one space. So does the Chicago Manual of Style. Many in-house style guides also request that writers use one space. So if you follow these style guides, the answer is pretty clear.

PR Daily readers, care to weigh in further on the spacing after a period debate?

Laura Hale Brockway is an Austin-based writer and editor and a regular contributor to PR Daily. Read more of her work at

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