Sometimes, in a writing skills blog, you’ll find yourself in a corner of the punctuation family tree where two symbols seem so suspiciously similar to each other you could imagine they are basically interchangeable.
Enter the dash and hyphen.
But wait. These actually have quite different purposes, and both are vital parts of the punctuation toolbox.
The lowdown
Dashes
Use them:
•   to go on to explain, paraphrase, or draw a conclusion from whatever you’ve just written (in this sense they act in much the same ‘arrow’ way as colons can do). For example:
It’s only rock and roll – but I like it.
•   in pairs, where you might otherwise use brackets – think of it as an aside that you want people to hear. Where brackets (or parentheses) can effectively tuck away such commentary (can’t they?), double dashes highlight it more. Either way, the sentence would still make sense if you lifted the section inside the punctuation out.
His favourite song – much to my embarrassment – was actually The Macarena.
•   to show a range or sequence – the dash replaces the word ‘to’. You don’t need spaces on either side.
1999–2001; 2007–09
London–Brighton bike race
9am–5pm.
Get to know them:
•   In Britain, generally we use the en-rule/en-dash (–). In the US, the longer em-rule/em-dash (—) is more common.
•   It is twice the length of the humble hyphen.
•   Put a space on either side of it, except when using it to show range or sequence.
•   In Microsoft Word, you can create an en-rule by holding down Ctrl followed by the subtract key (or numeric hyphen); if you want an em-rule, type Ctrl + Alt + subtract key. Alternatively, hold down Alt and type 0150 for an en-rule, or 0151 for an em-rule. Often, the AutoCorrect function automatically turns a typed hyphen into a dash (when you leave a space either side and continue the sentence), but it cannot always be counted on to do this, so check back.
•   In Mac OS, an en-rule is made by typing Option + hyphen. For an em-rule, it’s Option + Shift + hyphen.
Hyphens
Use them:
•   when joining words together in order to act as an adjective before a noun. This is known as an adjectival phrase and the hyphen makes clear which word is being modified. For example:
He’s a rocking-horse enthusiast.
Bread-making machines: imagine that!
There are twenty-odd members of staff at Emphasis.
Still not convinced? Well, compare the hyphen-less versions:
He’s a rocking horse enthusiast. (Loves headbanging; loves showjumping.)
Bread making machines: imagine that! (Run for the hills! The baked goods are getting organised!)
There are twenty odd members of staff at Emphasis. (We prefer the term ‘pleasingly eccentric’.)
•   for some compound terms, such as:
Eye-opener, cost-effective, up-to-date, self-assured.
If in doubt, look it up. If it’s not listed as one word or a hyphenated word, split it into two.
•   with prefixes, to distinguish from a deceptively similar word eg
I heard a confusing rumour by the water cooler: did Jones resign or re-sign?
•   for double-barrelled names:
Resign? Mr Spear-Shaker almost chased him out with a stick!
Get to know them:
•   No spaces on either side are needed.
•   Often used in web addresses (like www.writing-skills.com), where they are sometimes mistakenly referred to as a dash. If you want people to find your website, it’s important to get this right.
To sum up, we love dashes and hyphens – they are very useful for clarifying meaning – and hope that you will all be dash- and hyphen-lovers now, too.
