One Space or Two … The Debate Rages 

One space or two after the period? 

For some of us in the industry, this debate ranks right up there with other major life dilemmas like when to eat that avocado (right now), or whether to meet the employer match threshold on your 401K (always). 

Finally, researchers have stepped in and settled it for us. Sort of. 

“The rules of spacing have been wildly inconsistent going back to the invention of the printing press. The original printing of the U.S. Declaration of Independence used extra long spaces between sentences. John Baskerville’s 1763 Bible used a single space,” writes Avi Selk in the Washington Post. “WhoevenknowswhateffectPietroBembowasgoingforhere.Single spaces. Double spaces.  Em spaces.   Trends went back and forth between continents and eras for hundreds of years, Felici wrote.It’s not a good look.”

Selk reports on recent research from three Skidmore College professors who sifted through all the previous studies of the sort, seeking answers to this hot-button issue. (And yes, if you work in content and/or design, it IS a hot-button issue, right up there with the Oxford comma. Don’t get me started.)

“However,” they wrote, “to date, there has been no direct empirical evidence in support of these claims, nor in favor of the one-space convention.” 

So they did their own studies, slapping eye-tracking equipment on some 60 students and having them read text in both single and double space formats.

“And the verdict was: two spaces after the period is better.  It makes reading slightly easier,” notes Selk.

Now before all you double-spacers start gloating, here’s the rub. The test was inherently flawed.

“Most notably, the test subjects read paragraphs in Courier New, a fixed-width font similar to the old typewriters, and rarely used on modern computers,” Selk explains. Modern typesetting has evolved to take spacing and visual cohesion into account, and type designers spent huge amounts of time making sure to get this right. 

“Johnson, one of the authors, told Douglas that the fixed-width font was standard for eye-tracking tests, and the benefits of two-spacing should carry over to any modern font,” Selk continues. (It doesn’t, according to the designers I talked to. In fact, one of them actually let out a little shudder, poor guy.)

Either way, the research showed only a minor difference in reading speed, and basically no change in reading comprehension. 

“The major reason to use two spaces, the researchers wrote, was to make the reading process smoother, not faster,” Selk explains.  “Everyone tended to spend fewer milliseconds staring at periods when a little extra blank space followed it.”

Regardless, from a design standpoint, it’s time to drop the double space, and embrace the single. Unless you’re typing in Courier New.    Then take all the space you need.