Hyphen, en dash, em dash: what each mark is for

The three marks differ in length and in purpose. From shortest to longest they are the hyphen -, the en dash –, and the em dash —. The names of the two dashes come from old typesetting: the en dash is roughly the width of a capital N, and the em dash roughly the width of a capital M. Length is the visible difference, but the job each one does is what matters, and that is what this guide is built around.

The hyphen: joining words

The hyphen is the short one, and it lives on your keyboard. Its job is to join. The most common use is the compound adjective, where two or more words act as a single modifier before a noun. A writer who is well known is a well-known writer. A decision made at the last minute is a last-minute decision. The hyphen tells the reader to read the joined words as one unit modifying the noun.

The hyphen also breaks a word at the end of a line, joins some prefixes to their stems (as in re-enter or self-aware), and links spelled out numbers (as in twenty-three). A useful rule for compound adjectives: hyphenate them before the noun, but usually not after. "A well-known writer" takes the hyphen, while "the writer is well known" does not, because the words no longer sit together as a single modifier ahead of a noun.

The en dash: spanning a range

The en dash is the medium one, and it is not on a standard keyboard. Its main job is to show a span or range, where it stands in for the words "to" or "through". A range of years looks like 2019–2023. A page range looks like pages 45–60. A score looks like a 3–1 win. In each case the en dash means "from this to that".

The en dash has a second job: connecting two things of equal weight, often where "and" or "versus" or "between" is implied. A route between two cities is the London–Paris route. A clash between two camps is the liberal–conservative divide. A joint effort can be the Smith–Jones report. Here the en dash signals a relationship between two equals, which a hyphen, the mark of fusion into one unit, would not convey correctly. One caution: do not mix the en dash with the words it replaces. Write 2019–2023 or write "from 2019 to 2023", but not "from 2019 – 2023".

The em dash: a break in the sentence

The em dash is the long one, and it is the most expressive mark in English punctuation. Its job is to set off a break in a sentence, and it can do the work of three other marks depending on how you use it. Used in a pair, em dashes fence off an interruption the way parentheses or a pair of commas would: The witness, who arrived late, said nothing can become The witness—who arrived late—said nothing. The dashes give the aside more emphasis than commas and more energy than parentheses.

Used singly, an em dash introduces a sharp turn or a payoff at the end of a sentence, much like a colon but with more drama: She knew exactly what was missing—the signature. It can also mark an abrupt stop or a change of direction in dialogue and informal prose. The em dash is versatile, which is also its trap: a page peppered with them starts to feel breathless and loose, because every sentence seems to lurch sideways. Reserve it for the genuine break and let commas and full stops carry the ordinary load.

Spacing and house style

Whether you put spaces around a dash is a style decision, not a grammar rule, and the two big conventions disagree. Most US style guides, including Chicago, set the em dash tight against the words on both sides, with no spaces, like word—word. Many British house styles and most newspapers avoid the closed em dash and instead use a spaced en dash for the same job, like word – word. Both read cleanly. What matters is that you pick one and use it everywhere in a single piece, because switching between them looks careless to an editor.

How to type the en dash and em dash

Since neither dash sits on the keyboard, you need a shortcut. On Windows, hold Alt and type 0150 on the numeric keypad for an en dash, or 0151 for an em dash. On a Mac, press Option plus the hyphen key for an en dash, and Shift plus Option plus the hyphen key for an em dash. Most word processors and many editors auto-correct as well: typing a word, two hyphens, and another word often converts the -- into an em dash, and a spaced single hyphen into an en dash.

In HTML and on the web, the named entities – and — produce the en dash and em dash, which is how the examples on this page are encoded. If you are writing somewhere that strips the special characters, a plain hyphen for a range or a spaced hyphen for a break is an acceptable fallback, though the proper marks read more cleanly when they survive.

A quick way to choose

When you are stuck, ask what the mark is doing. Are you joining words into one unit, like a compound adjective? Use the hyphen. Are you showing a range or a link between two equal things, like years or cities? Use the en dash. Are you breaking the sentence to insert an aside or to land a turn? Use the em dash. Join, span, break. Those three verbs map cleanly onto the three marks, and once the verb is clear the choice usually follows.

What to do next

Run your draft through the Phrasit grammar checker to catch places where a hyphen was used for a range or a dash was used where a hyphen belongs. Use the find and replace tool to convert stray double hyphens into the proper mark in one sweep, and the text formatter to normalise the spacing around your dashes so the whole document follows one convention.