There are three commonly-used dashes, which are distinguishable by their length:

  • The hyphen: -
  • The en dash: –
  • The em dash: —

The em dash should not be used.

The en dash should be used in place of brackets or commas to add supplementary information to a sentence. It should be surrounded by spaces.

For example:

  • The Royal School of Mines – which became part of Imperial College London in 1907 – was established in 1851.

The en dash should also be used for years, to join terms of equal weight, or to represent a pause in the text.
For example:

  • 2015–16 academic year
  • Myers–Briggs profile
  • In May 1851 Hyde Park hosted The Great Exhibition of the Works of Industry of all Nations (or ‘The Great Exhibition’) – the first event of its kind in the world.

Slash (/)

Avoid using the slash in prose, such as ‘he/she’ or ‘from/to’ and instead rewrite the text to render it unnecessary. For example:

  • Departments will also look at your son/daughter’s interest in their subject.
  • Departments will also look at your child’s interest in their subject.


A hyphen should be used to join two word adjectives together, and for some words beginning with prefixes such as co, de, pre or re.

For example:

  • First-year students
  • Third- and fourth-year students
  • 19th-century history

Find out more

Check the spelling section for the preferred spelling of many commonly hyphenated words.