One Space or Two After a Period? Why the Rule Changed
- admin414426
- Aug 5
- 4 min read
If you learned to type before the widespread use of computers, you may have been taught to press the space bar twice after every period. If you learned later, you were probably taught that one space is correct.
So, who is right?
The short answer is that two spaces were appropriate for the technology people were using at the time. Modern publishing uses one space because today’s fonts and typesetting software create appropriate spacing automatically.
Why Did People Use Two Spaces After a Period?
Long before typewriters, professional typesetters often placed additional space between sentences. The amount varied considerably depending on the era, printer, and style of typesetting.
Then typewriters arrived.
Most traditional typewriters used monospaced type, meaning every character occupied exactly the same amount of horizontal space. A narrow letter such as i took up as much room as a wide letter such as m. This made typewritten text look less visually fluid than professionally typeset text.
Adding a second space after a period created a stronger visual break between sentences. Typing teachers began instructing students to press the space bar twice after sentence-ending punctuation, and generations of typists learned that this was the correct way to format a document.
It was not a pointless rule. It was a practical solution for the limitations of the equipment available at the time.
What Changed?
Computers and modern word-processing programs changed typography.
Most fonts used today are proportionally spaced. In fonts such as Times New Roman, Garamond, Georgia, and Arial, each character receives the amount of space it actually needs. The software also controls the spacing around punctuation and between words.
That means writers no longer need to manually create a larger gap between sentences. The font and typesetting software are already doing the visual work.
Once proportionally spaced fonts became standard, the extra space began to look unnecessarily large. It could create uneven gaps throughout a paragraph, particularly in justified text, ebooks, and professionally designed books.
The publishing industry gradually standardized the use of one space after sentence-ending punctuation.
When Did the Rule Officially Change?
There was no single day when the world collectively abandoned the second space. The transition happened gradually as typewriters gave way to word processors and desktop publishing.
The history is also more complicated than the popular explanation that “typewriters used two spaces and computers use one.” Professional printers had used several different sentence-spacing systems long before the typewriter existed.
The Chicago Manual of Style provides an interesting timeline. Its 13th edition, published in 1982, showed two spaces in its sample typewritten manuscript. The 14th edition, published in 1993, showed one. The 15th edition, published in 2003, explicitly recommended using one space after a period in typed manuscripts.
Today, major style guides—including Chicago, AP, and APA—recommend one space after a period.
Are Two Spaces Grammatically Incorrect?
Not exactly.
The number of spaces after a period is a matter of formatting and style, not grammar. Using two spaces does not make a sentence grammatically incorrect or change its meaning.
However, it is no longer standard practice in professional publishing. Editors routinely remove double spaces from manuscripts because books, ebooks, websites, and other professionally formatted materials are designed around single spacing.
A manuscript filled with double spaces may also suggest that the author is following an outdated formatting convention. It is a small detail, but publishing is an industry in which small details matter.
Do Two Spaces Make Text Easier to Read?
Some people genuinely find two spaces easier to read, particularly if that is how they learned to type.
A small 2018 study found a slight reading-speed benefit for participants who already used two spaces, but it found no improvement in reading comprehension. The results were not strong enough to overturn the publishing industry’s established preference for one space.
In other words, two spaces may feel more comfortable because they are familiar. That does not mean modern text requires them.
What Should Authors Use in Their Manuscripts?
Authors should use one space after periods, question marks, exclamation points, and other punctuation that ends a sentence.
This applies to:
Fiction and nonfiction manuscripts
Book descriptions and marketing copy
Blog articles
Websites
Newsletters
Social media content
Business documents
Print and ebooks
If a publisher, academic institution, employer, or client supplies a different style guide, follow its requirements. Otherwise, one space is the current professional standard.
How to Remove Double Spaces from a Manuscript
If double spacing is an ingrained habit, you do not have to correct every instance manually.
In Microsoft Word or Google Docs:
Open Find and Replace.
Enter two spaces in the Find field.
Enter one space in the Replace field.
Select Replace All.
Repeat the process until the program reports that no additional double spaces were found.
Repeating the search matters because a document may contain three or more consecutive spaces.
Be careful if your manuscript contains specially formatted material, such as tables, poetry, or intentionally spaced text. Review those sections separately before making a document-wide change.
The Bottom Line
People used two spaces because older typing and typesetting practices called for a more visible separation between sentences. The convention made sense on monospaced typewriters and became deeply embedded in typing instruction.
Modern fonts and publishing software no longer need that assistance. Today, one space after a period is the accepted standard.
So, if you still automatically press the space bar twice, you were not taught incorrectly. You were taught the correct convention for a different era of technology.
Publishing simply moved on—and took the extra space with it.
At Keele Publishing, our editors help authors prepare polished, professional manuscripts that meet modern publishing standards. From developmental editing to proofreading, we make sure the smallest details support the quality of the story you worked so hard to tell.
Need an editor for your manuscript? Contact Keele Publishing to learn more about our professional editing services.
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