Do you use one space or two after periods? Many people are surprisingly (even ridiculously) passionate about this issue.
The Two-Space Camp
Those who favor two spaces believe their text is more readable. Typically they learned to type on a typewriter. The two-space camp has recently gained some support from researchers who argue that reading comprehension improves slightly with two spaces after periods.
Putting two spaces after periods (and also after question marks, exclamation points, and colons) is a convention that evolved largely because typewriters were equipped with only mono-spaced fonts that allotted the same amount of space to every letter of the alphabet. The skinny letter I, for example, got the same real estate as the wide letter W.
The result is a lot of empty space, not only between sentences but within them—and even within individual words.
To make sure readers could easily distinguish between those insignificant spaces and the spaces that signaled the ends of sentences, typists put two spaces after end punctuation and colons.
The One-Space Camp
Those who prefer using only one space most likely learned to type on computers and were taught to use only one space.
Word processors give us the option of choosing fonts with proportional spacing, including Times New Roman, Georgia, Verdana, and Arial. With these fonts, the skinny letters of the alphabet take up less space than the wider ones, and—at least in theory—it is easier to see where sentences begin and end.
A Longstanding Debate
The one-space-versus-two debate has raged throughout the history of printing. (The article cited in the second paragraph above traces the debate back to the Declaration of Independence and to early printed versions of the Judeo-Christian Bible.)
Generally speaking, professional typographers have always had the option of using only one space because they use proportionally spaced fonts, which do not require the extra spaces in order for a series of sentences to be readable. Pick up any book published in the last century—even those published back before we had computers—and you will likely find only one space after periods (and other end punctuation and colons).
My Advice
Simply be consistent. A reader is more likely to be distracted (albeit subconsciously) by inconsistent spacing than by the consistent use of either one or two spaces between sentences. And of course, if you choose a word processing font that is mono-spaced—such as Courier New, Lucida Console, and Andale Mono—then you will likely want to use two spaces.
Some of us who learned to type on typewriters find it challenging to shed the old two-space habit. Just to be sure I am being consistent, I use the global find-and-replace function, finding all instances of two spaces and replacing them with one. The process takes about three seconds.
For insight into the many arguments for one space or for two, read this article—and especially the lengthy discussion in the comments section.
Copyright 2018 Get It Write. Revised 2019.