Quick answer: A hyphen (-) joins words, as in well-known or mother-in-law. An en dash (–), roughly the width of a capital N, links ranges and pairs — read it as "to" or "through," as in pages 10–20 or the New York–London flight. An em dash (—), about the width of a capital M and the longest of the three, breaks into a sentence—like this—doing the job of commas, parentheses, or a colon.
The three marks at a glance
- Hyphen (-) — joins. Builds compound words and compound modifiers: part-time, twenty-one, a well-known actor.
- En dash (–) — spans. Shows ranges and connections; you can usually replace it with "to" or "through": 1914–1918, Monday–Friday, the London–Paris route.
- Em dash (—) — breaks. Interrupts a sentence for emphasis, an aside, or a sudden turn: She had one plan—escape.
Learn those three verbs — join, span, break — and you have ninety percent of it. The rest is detail.
The hyphen: joining words
The hyphen is the short one on your keyboard, and it lives inside or between words rather than between clauses. Use it to:
- Join compound modifiers before a noun: a well-known actor, a state-of-the-art studio, a five-year-old child, a low-cost option.
- Form compound nouns: mother-in-law, self-esteem, editor-in-chief, merry-go-round.
- Spell out numbers and fractions: twenty-one, ninety-nine, two-thirds full.
- Attach some prefixes, often to avoid confusion: re-sign a petition (not resign your job), re-creation versus recreation, ex-husband, co-op.
A key rule: hyphenate a compound modifier before the noun, but not after it.
- ✓ a well-known author / ✓ the author is well known
- ✗ a well known author / ✗ the author is well-known
And never hyphenate after an adverb ending in -ly — the -ly already does the joining:
- ✓ a highly regarded surgeon
- ✗ a highly-regarded surgeon
The en dash: spanning ranges and connections
The en dash is the middle length, and most people have never deliberately typed one. It has two main jobs:
- Ranges of numbers, dates, times, and pages, where it means "to" or "through": pages 30–45, the 1939–1945 war, open 9 a.m.–5 p.m., ages 5–11.
- Connections and pairings between two things of equal weight: the London–Paris route, the doctor–patient relationship, US–China relations, a 3–1 win.
Correct versus incorrect for a range:
- ✓ See pages 10–20. / ✗ See pages 10-20. (a hyphen is too short for a range)
There is also a tidier, more advanced use: an en dash links a prefix or single word to an open compound — one that already contains a space.
- ✓ post–World War II economics
- ✓ a Pulitzer Prize–winning novel
- ✗ post-World War II economics (a hyphen wrongly binds only "post" to "World")
One common trap: don't use an en dash once you've written from or between. Pair from with to, and between with and:
- ✓ from 1990 to 1995 / ✗ from 1990–1995
- ✓ between 40 and 50 people / ✗ between 40–50 people
The em dash: breaking into a sentence
The em dash is the long, dramatic one — the closest punctuation has to a spotlight. Use it to:
- Set off an aside, more forcefully than commas or parentheses: My brother—the tall one—runs marathons.
- Introduce a summary or punchline, where a colon would feel flat: She wanted one thing—to win.
- Mark a sudden break or interruption, especially in dialogue: "Wait, I didn't—" he began.
A pair of em dashes works like stronger brackets; a single em dash works like a colon with attitude. Correct versus wrong:
- ✓ The verdict—guilty on all counts—stunned the room.
- ✗ The verdict - guilty on all counts - stunned the room. (spaced hyphens are not a dash)
Used well, the em dash is punchy. Used every other line, it turns prose breathless — so reserve it for moments that earn the drama.
US vs UK: the difference that genuinely matters
This is where style guides split, so match your audience. The disagreement is only about the sentence-level dash — the parenthetical or "break" dash:
- US (Chicago Manual of Style): a closed-up em dash with no spaces — the plan—her plan—worked.
- US journalism (AP style): the exception — a spaced em dash — the plan — her plan — worked.
- UK (Oxford, the Guardian, most British publishers): a spaced en dash does the job — the plan – her plan – worked.
So the same aside is word—word in an American book, word — word in a US newspaper, and word – word in a British one. All three are correct in their home style; the only real error is mixing them on one page. Note that the ranges rule (en dash) and the joining rule (hyphen) are the same on both sides of the Atlantic.
A memory trick
The names give the widths away: an en dash is about as wide as a capital N, an em dash as wide as a capital M — and because M is wider than N, the em dash is the longer mark. For the job each does, try swapping the dash for a word: if "to" or "through" fits, you want an en dash (10–20 = 10 to 20); if "namely" or a pair of brackets fits, you want an em dash.
How to type them
- Mac: en dash = Option + hyphen; em dash = Option + Shift + hyphen.
- Windows: en dash = Alt + 0150; em dash = Alt + 0151 (using the numeric keypad).
- Word and Google Docs: type two hyphens between words (word--word) and autocorrect turns them into a dash. That typewriter-era double hyphen is still an accepted stand-in when you genuinely can't produce a real dash.
Frequently Asked Questions
What is the difference between a hyphen and a dash?
A hyphen (-) is shorter and joins words into compounds, like "well-known" or "twenty-one." A dash is longer and separates parts of a sentence. There are two dashes: the en dash (–) for ranges like "10–20," and the em dash (—) for breaks and asides—like this. In short, hyphens link words; dashes divide thoughts.
Do you use an em dash or en dash for date ranges?
Use an en dash (–) for date and number ranges: "1914–1918," "pages 20–35," "ages 5–11." Read it as "to" or "through," and never use the longer em dash or the shorter hyphen for a range. One exception: if you've written "from," pair it with "to"—write "from 1914 to 1918," not "from 1914–1918."
Should there be spaces around an em dash?
It depends on your style. The Chicago Manual of Style (US books) sets em dashes closed up, with no spaces—like this. AP style (US news) adds a space on each side — like this. British publishers usually skip the em dash and use a spaced en dash instead – like this. Pick one convention and stay consistent throughout.
Are em dashes a sign of AI writing?
No. The em dash is centuries-old punctuation used by Austen, Dickinson, and Dickens, and it remains standard in professional writing today. AI tools happen to use it often, so some readers now notice it—but a well-placed em dash signals a careful writer, not a robot. Don't abandon a correct mark over a passing suspicion.
How do I type an em dash and an en dash?
On a Mac, press Option + hyphen for an en dash (–) and Option + Shift + hyphen for an em dash (—). On Windows, hold Alt and type 0150 (en) or 0151 (em) on the numeric keypad. In Word or Google Docs, typing two hyphens between words auto-corrects into a dash.