An en dash looks like this “–”
A hyphen looks like this “-”
Some content management systems, including GOV.UK’s Publisher, do not recognise the en dash and will replace it with a hyphen. If in Microsoft Word, use en dashes.
Microsoft Word automatically converts hyphens to en dashes when they are preceded by a space. Elsewhere, you can use “Ctrl” and “-” (minus on the number keypad). Be aware that the minus sign and the hyphen are easily mistaken for each other.
Adding extra information
This is a good device for adding extra information that is not essential to the rest of the sentence. Be careful: these can make writing difficult to read if overused.
There are some statistics – fascinating ones at that – on the ONS website.
Breaking a sentence
This shows other kinds of break in a sentence where a comma, semicolon, or colon would be traditionally used.
There are some statistics on the website – they are fascinating
Consumer Services Price Indices – expected availability
Hyphens must be used for the following situations.
Hyphens have several specific uses. These are for linking, and for compound modifiers.
Use hyphens as prefixes and suffixes to words, or show that these are required for a word to be understood.
Henri IV betrayed his co-religionists
Hyphens are used for all words with “e” as a prefix, except for “email”.
Hyphens are used for all words with “co” as a prefix.
Hyphens are not used for words with “re” as a prefix, unless the word afterwards begins with an “e”.
If in doubt, check using the Oxford English Dictionary.
Hyphens are used in compound words where component words have a combined meaning or a relationship.
a five-storey building,
a well-explained report
the long-term effects.
However, if you use this after the subject of the sentence, it is not hyphenated.
a report that was well explained
It is best to check if the word is a compound modifier in the Oxford English Dictionary.
There is one exception to this rule. The term “police recorded crime” does not require a hyphen.