En dash and em dash: all you need to know

The en dash ( – ) is a little longer than a hyphen and marks ranges, scores, and connections, as in chapters 1–5. The em dash ( — ) is the longest of the three and sets off an aside or a break in a sentence, in place of commas, parentheses, or a colon.

You probably use most punctuation marks with care. You don't add too many question marks to your questions or overuse the exclamation point. You know how to use a comma and when to use a semicolon. Hyphens, apostrophes, and ellipses are no problem for you. But do you know the two "brothers" of the hyphen, the en dash and the em dash? This article explains what each one is for and how to type it.

The en dash

The en dash ( – ) is wider than the hyphen but narrower than the em dash. Its name comes from its width: it is about as wide as the letter N. Generally, the en dash connects two items or sets them in relation to each other. Use it in the following cases.

Ranges of numbers

The en dash marks a span of time, a range of dates, or a range of numbers. It stands with no space before or after it, and you read it as "to" or "through".

For tomorrow, please read chapters 1–5.

My office hours are Monday–Wednesday, 9:00 a.m.–11:00 a.m.

Do not use the en dash after from or between. With those words, write the range out in full:

For tomorrow, please read chapters 1 to 5.

My office hours are from Monday to Wednesday, between 9 a.m. and 11 a.m.

Scores

Game scores and contest results are also written with an en dash, with no space on either side.

The 2014 World Cup final between Germany and Argentina ended 1–0.

Conflicts, connections, and directions

Between words that name a conflict, a connection, or a direction, an en dash is common too, again without spaces.

Expect a delay on the London–Paris flight.

The em dash

The em dash ( — ) is the widest of the three marks, about as wide as the letter M. It is very versatile: depending on the context, it can replace commas, parentheses, or a colon.

While the en dash stands without spaces, the em dash may have a space on each side or none, depending on your style guide. Most American style guides, such as the Chicago Manual of Style, use no spaces; AP style puts a space on each side. Many British publishers use a spaced en dash ( – ) where American style uses an em dash. Whatever you choose, keep it the same throughout a text.

In place of commas

A pair of em dashes can replace a pair of commas around an aside. Unlike commas, the dashes give extra emphasis to the part they enclose.

When he saw her again—something he had waited for impatiently since their last call—his heart skipped a beat.

In place of parentheses

Content that is usually set off by parentheses can also be set off by em dashes, which draw more attention to it. If you want to be subtle, stay with the parentheses. If you want to draw attention to the aside, em dashes are a good stylistic choice.

When Martha's favorite cat—she owned 23 of them—got sick, she wasted no time taking it to the best-known vet in town.

In place of a colon

In informal writing, an em dash can replace a colon that introduces the conclusion of a sentence. In formal writing, use the colon.

After that day, Marty knew one thing for sure—if he ever moved away from New York, his new home would be Paris.

Several em dashes for missing content

Two or three em dashes in a row show that something has been left out, either because it is unknown or because it is omitted on purpose. A 2-em dash (two em dashes in a row) stands for the missing part of a word, and a 3-em dash (three in a row) stands for a whole missing word. Use the same length no matter how many letters are missing, and stay consistent throughout your text.

The letter was signed by a Mr. J——.

The suspect, ———, was convicted by the state of Illinois.

Overview

Many word processors also turn two hyphens typed between two words into a dash automatically. For more on telling the marks apart, read dashes and hyphens: what is the difference?, and for the hyphen's own rules, all you need to know about the hyphen.