Three Lines, Three Jobs

The hyphen (-), en dash (–), and em dash (—) look similar on the page, but they serve completely different purposes. Mixing them up is one of the most common typographic errors in English writing, and learning the difference takes about five minutes.

The Hyphen (-)

The hyphen is the shortest of the three and the one you already know. It joins words together.

Use it for: compound modifiers before a noun ("well-known author," "high-quality work," "two-thirds majority"), compound numbers ("twenty-one"), and prefixed words where clarity requires it ("re-enter," "co-worker").

Do not use it for: separating clauses, indicating ranges, or adding dramatic pauses. Those jobs belong to the other two dashes.

A quick test: if you are connecting words into a single concept, use a hyphen.

The En Dash (–)

The en dash is slightly wider than a hyphen, roughly the width of the letter "N," which is how it got its name. Its primary job is to indicate ranges and connections.

Use it for: number ranges ("pages 15–32," "the 2020–2025 period"), scores ("the team won 4–2"), and connections between equal items ("the London–Paris flight," "the liberal–conservative divide").

The rule of thumb: if you can substitute the word "to" or "through," use an en dash. "Pages 15 to 32" becomes "pages 15–32."

On most keyboards, you can type an en dash with Option+Hyphen on Mac. On Windows, use Ctrl+Minus on the numeric keypad or type the word and let autocorrect handle it in most word processors.

The Em Dash (—)

The em dash is the longest of the three, about the width of the letter "M." It is the most expressive punctuation mark in English and does the work of commas, parentheses, and colons depending on context.

Use it for: interruptions and asides ("The project — which was already behind schedule — hit another setback"), dramatic pauses ("She opened the door — and froze"), and amplification ("He had one goal — survival").

The em dash adds emphasis that commas and parentheses do not. A parenthetical aside in commas feels quiet. The same aside in em dashes feels urgent or important.

On Mac, type Option+Shift+Hyphen. On Windows, use Alt+0151 on the numeric keypad.

The Practical Summary

Hyphen (-): joins words. "State-of-the-art design."

En dash (–): connects ranges and pairs. "Chapters 3–7."

Em dash (—): sets off clauses with emphasis. "The answer — surprisingly — was no."

Get these three right, and your writing will look noticeably more polished than the majority of text published online.