The Great Em Dash Spacing Debate
One of the most frequently asked questions in English typography is whether an em dash should be surrounded by spaces. Unlike periods and commas, where the spacing rules are universal, em dash spacing is determined by the style guide you follow.
Comparison by Major Style Guides
| Style Guide | Spacing Rule | Example | Primary Industry |
|---|---|---|---|
| Chicago Manual of Style (CMOS) | No Spaces | word—word |
Book publishing, literary magazines, academic presses |
| APA Style (7th Edition) | No Spaces | word—word |
Scientific papers, psychology, social sciences |
| MLA Style (9th Edition) | No Spaces | word—word |
Humanities, literature, high school & college essays |
| Associated Press (AP Style) | Spaces on Both Sides | word — word |
Newspapers, online journalism, public relations, press releases |
| Oxford / British Style | En Dash with Spaces | word – word |
UK and Commonwealth publishing |
Why Does AP Style Use Spaces?
In narrow newspaper columns, an unspaced em dash between two long words can force an awkward line break or create excessive letter-spacing gaps. By requiring a space on either side of the em dash (word — word), news publishers allow web and print typesetting engines to break lines naturally around the punctuation.
Why Chicago & Literary Styles Forbid Spaces
Traditional book typographers argue that adding standard word spaces around a wide em dash creates an unsightly visual "hole" in a line of justified body copy. In formal book publishing, the em dash is set closed-up against the adjacent letters (word—word).
The Golden Rule: Consistency
Whichever style you choose for your publication, the most important editorial principle is internal consistency. Mixing spaced and unspaced em dashes within the same document makes writing look unpolished.
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