Do you know the difference between a hyphen and a dash? An em-dash and an en-dash? Do you know the different situations where they should all be used? Or are you just using whatever dash-shaped symbol you can find on your keyboard or in Word's auto-formatting? If you want to score some serious grammar points, come in and read up on all the different dashes you should be using.
There are five-ish kinds of dashes commonly used in the written English language: though it could me more or less depending on what you count as a dash. The main ones are the hyphen (-), en-dash (–) and em-dash (—).
The fourth kind we're counting is the horizontal bar (―), though in many fonts it appears the same as the em-dash, and they can be used interchangeably. If you do want to get fancy with a horizontal bar, its second name, the quotation dash, will give you an idea of what it's used for. The horizontal bar is generally used to either introduce quotes or attribute quotes to their authors, but both of these can also be done with an em dash.—Hayley Williams
While the hyphen isn't actually a dash at all, it's the only dash-like punctuation available on most keyboards: meaning it often gets used in place of a dash both accidentally and purposefully. The difference between a hyphen and a dash is this: a dash is used as part of a sentence, while a hyphen is part of a word.
So hyphens are used, unsurprisingly, for hyphenated words or phrases like state-of-the-art or 10-year-old or Spider-Man. They're often used to create what are called compound adjectives in places where the sentence would otherwise be confusing, such as "a concealed weapons permit". Is it the permit that's concealed, or the weapons? To clarify, you'd hyphenate concealed-weapons.
Some phrases are always hyphenated, (like Spider-Man, dammit) while others are never hyphenated, such as 'high school'.
Hyphens are sometimes used to indicate ranges such as '200-300 participants' but en-dashes are more often used for this purpose.
The en-dash is longer than a hyphen, but shorter than an em-dash, and almost exclusively used to indicate ranges of things. Most often these are ranges of numbers or dates, and are used without spaces in between: June–July 2018, pages 2–6, 1987–90.
These can also be used to indicate relationships between things, such as 'a mother–daughter relationship' or 'the Sydney–Tokyo flight'. Many of these can be down to house style or personal preference, so if you're unsure either check with your editor or just go with what your heart tells you.
The last case you would use an en-dash is in place of a hyphen when one of the words being hyphenated is already an open compound (ie, a compound without a hyphen), like ex–prime minister, a term we use pretty often here in Australia.
Now we get to all journalists' favourite kind of dash — the em-dash. While the other two are mainly used within single words or compounds, the em-dash is used to punctuate sentences. You'll often find it used interchangeably with colons or parentheses, whether that preference is the personal decision of the author or a house style. Usually it's just a bad habit that the author needs to break out of, however.
The em-dash is considered to be a bit of punctuation that's stronger than a comma but not as strong as a full stop. You can use it to interject in the middle of a sentence — often to explain or define something relevant — or in more casual writing, to indicate a thought change or abrupt interruption.
Microsoft Word's default auto-formatting will insert an em dash if you type a space, hyphen and space ( - ) between two words, while many people type it as a double hyphen (—) when typing on the fly. More correctly it should be a double en-dash, but sometimes you just want to use the keys that are on your keyboard.
Of course like everything in the English language, all these dashes and more have many obscure rules surrounding them, but now you at least know the basics of hyphens and dashes.