How Many Spaces After a Period

I was delivering a training program at a company in Detroit when one student asked if they should put one space or two spaces after each period. They had just completed a proposal and had been struggling internally with this question.

The camp that advocated two spaces argued that the major style guides were in agreement that there should be two spaces after each period, and anything else would be unprofessional. Until recently, I shared this view. When I was taught to type (on a state-of-the-art IBM Selectric typewriter at Oak Hills High School in Cincinnati), Mr. Hauck drilled into our high school heads that you put two spaces after each period. No exceptions. Considering how well I was taught, even pondering a single space seemed on par with religious blasphemy.

Today, though, I’m firmly in the “single space” camp and here’s why.

In the old typewriter days, text was necessarily left justified; everything except the indented first line was flush left, and the right side of the paragraph had a ragged, jagged edge. In contrast, most word processing software today includes the capability to fully justify a paragraph so it is flush to both the left and right edges. I generally select this option because I think a document looks better when it’s fully justified than when it’s left justified.

Here’s the problem.

In order to make a line justified to the left and right, the software has to stretch each line of text to make it fit. If you have two spaces after each period, fully justified formatting can turn your two spaces into a fairly sizeable gap. In fact, it can create a gap so large it looks like an error the proofreaders missed. And that looks funny. And unprofessional.

Therefore, while I recognize I am recommending people ignore most of the generally accepted style manuals, I continue to advocate a single space after each period instead of a double space.

I feel like such a rebel.


David Seibert is a professional salesperson and consultant for businesses that respond to formal procurements in non-federal markets. Dave publishes a comprehensive curriculum of online, self-paced proposal training classes, delivers onsite and online proposal training programs for dedicated proposal teams, and provides proposal and business development consulting services for businesses that want to improve their win rates. 

Dave is founder and president of The Seibert Group, a proposal consulting and training organization serving businesses that sell to other businesses, A/E/C firms, schools, and to state and local governments. Dave authored the popular proposal book, Proposal Best Practices, is active with the Association of Proposal Management Professionals (APMP), and is a member of the APMP Speakers Bureau. You can contact Dave at [email protected].

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