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Hyphens, en dashes and em dashes: how to use them

They might all look vaguely similar, but hyphens and dashes serve very different purposes. Here’s a quick rundown of their differences and how to use them.

Hyphen ‐

The hyphen is shorter than both dashes (although in some typefaces, it can look identical). It has two purposes in writing and typography: joining words and splitting words.

Joining words

When two words (or a word and a prefix/suffix) are being made into one, they are joined by a hyphen. Hyphens are often used to join two parts of an adjective to prevent ambiguity. Consider:

  • a cold-blooded animal (the blood is cold, not the animal that happens to have blood)
  • a second-hand clothes shop (the clothes are second-hand)
  • a six-year-old girl (the girl is six years old)
  • there were six year-old girls (there were six girls who were 12 months old)

When a hyphenated word comes into popular usage, it usually loses its hyphen. Nobody would describe an aircraft as being super-sonic any more.

Splitting words

In typography, if a word is so long that it would cause unacceptable word spacing if it were to go on the next line, it can be split with a hyphen. In word processors, you can specify that a hyphen is optional. That means that if the whole word fits on a line, it will not be broken, but if it doesn’t you can specify where it will split.

It’s good practice to split words as naturally as possible, so the reader gets an idea of the pronunciation. That usually means splitting at the end of each syllable.  For example:

  • man-slaughter, not mans-laughter
  • co-operate, not coop-erate
  • Mersey-side, not Mers-eyside
  • proof-read-ing, not pro-ofre-ading

Don’t split words with one syllable.

As a copywriter, I don’t really need to worry about this kind of hyphenation because I don’t really know where individual words will appear on the page. It’s a job for typesetters and designers.

Splitting hyphenated words

If a word is naturally hyphenated, it is bad practice to split it anywhere else if it doesn’t fit on the line. If the natural hyphen cannot be used to break to word, consider changing the letter spacing or word spacing.

Hyphens and word counts

A hyphenated word counts as one word. However, most word counts are specified for visual reasons, so don’t worry if you have a lot of hyphenated words and the count seems low. Usually, a single hyphenated word will count as two from a design perspective.

Do Hyphenated Words in Title Case Have Capitals?

Whether hyphenated words in title case* have both component words starting with a capital depends on the style. Technically, a hyphenated word is one word, so only the first letter should be capitalised. However, some styles demand that both, or all, component words, plus prefixes and suffixes, start with a capital.

* “Title case” is the heading style to this section, where each major words starts with a capital, as opposed to “sentence case”, where normal capitalisation is used (like all the other headings here).

En dash –

The en dash has three main purposes: as a bridge between items in a range; as a type of parenthetical symbol; or in place of a colon or semicolon. Its name comes from the fact that it’s the length of a lower-case letter n.

Bridging with an en dash

Where there’s a range of numbers, they can be shown with an unspaced en dash in place of the word “to”. It also works with letters, when they are being used alphabetically. So we can write:

  • The job will be ready in three to four days or The job will be ready in 3–4 days.
  • Complete sections A to E or Complete sections A–E

Note that there is no space before or after the dash. Typographically, however, the dash can be used to break over two lines, like a hyphen.

An en dash can also be used to denote journeys, periods of time or pieces of infrastructure. Again, the dash replaces the word “to”:

  • The Stockton–Darlington railway
  • The Victorian–Edwardian eras

Using bridging en dashes with units of measurement

If you’re using a dash to show a range of units, you only need to use the unit once.

  • 56–62 °C, not 56 °C–62 °C
  • 3–6 o’clock, not 3 o’clock–6 o’clock

If you want to avoid ambiguity by mentioning the unit twice, use the word “to” instead.

Note: a bridging en dash means “to”, not “and”

Avoid using an en dash to replace the word “and”, particularly when following the word “between”.

  • between 6 and 8 years, not between 6–8 years

En dash as a parenthetical symbol

The second use of the en dash is as a parenthetical symbol. Parentheses are the ( and ) symbols, often called brackets. That gives a clue to the use of en dashes in this context – they are used to separate a word, phrase or clause from the sentence that surrounds it. It’s useful for giving additional information or reminding the reader abut some previously mentioned fact. In most cases, the en dash can be swapped with parentheses, em dashes or commas and the sentence will work perfectly well.

Note that these en dashes are spaced; that is, they have a space before and after them.

  • The farmer – who had been watching closely – took aim and fired.
  • The farmer—who had been watching closely—took aim and fired.
  • The farmer (who had been watching closely) took aim and fired.
  • The farmer, who had been watching closely, took aim and fired.

However, if a sentence is long and convoluted, with several nesting parentheticals, it’s good to mix up the types to aid clarity.

  • The farmer – who had been watching closely and concluded (wrongly) that the foxes were after his chickens – took aim and fired.

is preferable to:

  • The farmer, who had been watching closely and concluded, wrongly, that the foxes were after his chickens, took aim and fired.
  • The farmer (who had been watching closely and concluded (wrongly) that the foxes were after his chickens) took aim and fired.

As a rule, the sentence should work equally well with or without the part that’s parenthesised.

  • The farmer took aim and fired.
  • The farmer – who had been watching closely and concluded that the foxes were after his chickens – took aim and fired.

En dash as a colon or semicolon

A spaced en dash can often replace a colon or a semicolon, and can be advisable if there are already (semi)colons in the sentence.

  • There was only one possible solution: jump.
  • There was only one possible solution – jump.

 

  • I like the summer; it reminds me of home.
  • I like the summer – it reminds me of home.

Em dash —

The em dash is the longest of the dashes, supposedly the length of a letter m (hence its name). It can be used parenthetically or to replace missing words or letters.

Em dash as a parenthetical symbol

The em dash has exactly the same parenthetical purpose as the spaced en dash above. Its use is purely a matter of style. Even parenthetically, it can be either spaced or unspaced, but note that unspaced em dashes do take up a lot or room and can look unsightly. The em dash is generally favoured in the US, whereas in the UK the en dash takes precedence; but there are no set rules here.

Em dash to replace missing words or letters

The em dash can be used to show hidden or missing text. That might be:

  1. to carry a plot (where the writer doesn’t want the reader to find something out
  2. where text is unknown or unknowable
  3. where expletives are used.

Examples:

  1. She finally worked out that C— was the murderer
  2. The ancient engraving said “Lorem I— dolor sit amet, c—tur adi—od tempor
  3. “Come back here, you f—g m—r,” she requested.

Photo: Kristaps Grundsteins