Illustration for Hyphen, En Dash, Em Dash: Three Marks, Three Jobs

Hyphen, En Dash, Em Dash: Three Marks, Three Jobs

ByNathan Cole

Three horizontal marks, increasing in length, doing unrelated jobs:

  • Hyphen – joins words
  • En dash – spans ranges
  • Em dash — interrupts sentences

The hyphen joins

The shortest mark, and the only one on a standard keyboard. It binds words into a single unit:

  • Compound adjectives before a noun: a well-known author, a two-hour delay
  • Some compound nouns: mother-in-law, self-esteem
  • Prefixes where the join would confuse: re-cover against recover
  • Spelled-out numbers: twenty-three

The compound adjective case is the one that comes up daily; our guide to hyphenating compound adjectives covers it properly.

The en dash spans

Named for the width of a capital N. It means to or through, and it connects things of equal weight:

  • Ranges: pages 40–58, 1914–1918, Monday–Friday
  • Connections between equals: the Paris–Berlin route, the Bose–Einstein condensate
  • Scores: a 3–1 win

Two things to watch. Do not mix it with from or between: write from 1914 to 1918 or 1914–1918, never from 1914–1918. And it takes no spaces around it in most styles.

The em dash interrupts

The width of a capital M, and the most useful of the three. It marks a break in a sentence:

  • An aside, in pairs: The results — and nobody expected this — were unanimous.
  • An abrupt turn: She had prepared for everything — except the weather.
  • An emphatic list introduction: Three things mattered — speed, cost and trust.

Against the alternatives: commas are the quietest, parentheses whisper, and em dashes announce. The same aside gets three different weights depending on which you choose, and that is a real decision rather than a matter of taste.

Spaces or no spaces

House styles disagree, and both are correct:

  • Chicago and most American publishing: em dash closed up—like this.
  • AP and most British publishing: spaced — like this.

Pick one and hold it. The inconsistency is what readers notice.

How to type them

  • Windows: en dash Alt+0150, em dash Alt+0151
  • Mac: en dash Option+hyphen, em dash Option+Shift+hyphen
  • Anywhere: most word processors turn — into an em dash automatically
  • HTML: – and —

If you only remember one thing

Using a hyphen where an em dash belongs is the common error, and it looks like a typo rather than a choice. If your sentence has a break in it, the mark should be long.

Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.

Nathan Cole writes the adjective guides and word lists on Grammar Simplified. Every guide he publishes is checked against Merriam-Webster for spelling and usage, the Chicago Manual of Style for punctuation, and the AP Stylebook where a convention is specific to web writing. Where a rule is genuinely disputed among those authorities, he says so in the guide rather than picking a side quietly. Corrections are welcome and get acted on — see the editorial policy.

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