A hyphen is the punctuation mark you should use to add clarity to some words.

An en-dash is longer than a hyphen, and we use it for specific purposes at the Office for National Statistics (ONS).

Hyphens

A hyphen is a symbol used to link words together.

Hyphens are used to clarify the meaning of different words, including prefixes and suffixes, when these are used together.

Joining words together

Use a hyphen to join words together to form a new word.

He liked his co-workers.

Use a hyphen to distinguish words from similar ones.

re-sort, not resort
co-op, not coop
re-form, not reform

Use a hyphen for all words with “e” before the word (as a prefix), except for “email”.

e-commerce
e-book
e-learning

Do not use hyphens for words with “re” as a prefix, unless the word afterwards begins with an “e”.

replay
rewrite
re-examine
re-evaluate

If you are unsure, check the word in the Cambridge Dictionary.

Compound modifiers

A compound modifier is two words that act as one adjective when joined by a hyphen.

Use hyphens in phrases where words have a combined meaning or a relationship.

a five-storey building
a well-explained report
the long-term effects

Do not use a hyphen when you use compound modifiers after the subject of the sentence.

a building with five storeys
a report that is well explained
the effects that are long term

If you are unsure, check if the two words are a compound modifier in the Cambridge Dictionary.

There are some exceptions to this rule.

Compound modifiers that do not need a hyphen are:

• police recorded crime
• civil rights movement
• financial services sector
• work inspection powers

Words that end in “ly”

Do not use hyphens after adverbs ending in “ly”.

a hotly disputed penalty
a constantly evolving newspaper
genetically modified food
statistically significant changes

Prefixes that do not need hyphens

The following prefixes do not need hyphens:

• macro
• mega
• micro
• mini
• multi
• over
• super
• under

macroeconomics
multimillionaire

En dashes

An en dash can be used:

• to add extra information to a sentence
• to break up a sentence
• in a headline

It should always have spaces on either side.

To use the en dash in Microsoft Word, use “ctrl” and “-” (minus on the number keypad). Be aware that the minus sign and the hyphen are easily mistaken for each other. If this does not work, you can click on “insert” in the top panel menu, then “symbols”, then “more symbols”, then “special characters”, and then “en dash”.

These functions may not work if you are using the browser version of Microsoft Word, so we suggest using the desktop app.

Adding extra information

The en dash adds extra information that is not essential to the rest of the sentence but may be useful for the reader. Overusing en dashes in this way can make your content difficult to read.

The motive behind acquiring competitors – referred to as horizontal integration – can be to increase market share and product range.

Breaking a sentence

There are other ways to use an en dash to break a sentence where a comma, semicolon, or colon would be traditionally used.

There are some statistics on the website – they are fascinating.

Labelling sources

We use an en dash in our chart and table sources to separate the department or organisation, and the survey or publication name.

Office for National Statistics – House Price Index