10.1.8. Dashes and hyphens
Dashes. Short (or ‘en’) dashes may be used to punctuate a sentence instead of commas or brackets (see Sections 10.1.6(c) and 10.1.7(a)). They increase the contrast or emphasis of the text thus set off. However, use sparingly; use no more than one in a sentence, or – if used with inserted phrases – one set of paired dashes. Avoid using dashes in legislation.
When citing titles of publications or documents, use a short dash to separate the title from the subtitle.
The long (or ‘em’) dash can be used as a bullet point in lists (see Section 5.7).
Hyphens. As a general rule, the first spelling given on the Oxford Dictionaries Premium website (subscription required), or on the Oxford Learner’s Dictionaries website, should be followed (making sure in each case that the British English dictionary is selected).
nouns composed of a participle plus preposition:
They discussed the buying-in of sugar.
compound adjectives preceding the noun that they qualify:
up-to-date statistics, long-term policies, foot-and-mouth disease
Exception: value added tax.
Do not hyphenate:
adverb-adjective modifiers when the adverb ends in -ly:
newly industrialised developing countries
adverb-adjective modifiers when ‘ever’ is followed by a comparative adjective:
ever closer union
Many phrases are treated as compounds, and thus need a hyphen, only when used as modifiers:
up-to-date statistics, but the statistics are up to date
long-term effects, but effects in the long term
Other adjectives always take a hyphen:
carbon-neutral energy sources, and energy sources that are carbon-neutral
Prefixes also take a hyphen:
anti-American, non-cooperative, co-responsibility levy, co-funded, self-employed
unless the prefix has become part of the word by usage:
cooperation, coordination, subsection, reshuffle, email
Either ‘en’ dashes or hyphens are used to join related or contrasting pairs:
the Brussels–Paris route / the Brussels-Paris route
a current–voltage graph / a current-voltage graph
Either ‘en’ dashes or hyphens are used to replace the word ‘to’ in a number or date range:
2010–2014 / 2010-2014