—This is an em dash. It is the width of a capital M.

–This is an en dash. It is the width of a capital N.

-This is a hyphen. It is the width of… er… a hyphen.

The hyphen is not a dash. It’s a hyphen—used to hyphenate things; intra-word punctuation, generally. It is not a replacement for any of the dashes.

Back in the day, when I was at uni, I handed in an assignment. It came back with various corrections and lines through things. One of the notes was: This should be an em dash.

‘What the fraggle is an em dash?’, I thought. And then class ended and I went to the bar.

A while later, we actually covered it in class, which was handy.

[MD: You once told me you’d done a whole-semester subject called ‘Em Dashes 101’. And I believed you.]

When I explain these things in the courses I run, I explain it like this:

The em dash is your general purpose dash. It does the heavy lifting. In most cases, this is the dash you are looking for.

The em dash is used to:

  • indicate an expansion, or a quick shift in thought
    • Many people avoid the em dash, because they think they may bite—but no one’s been bitten in decades!
  • set something aside parenthetically
    • David Bowie—during his Eye Patch Phase—famously arrived at a show dressed as a Scottish pirate, riding a giraffe. [No, not really.]
  • indicate a break  in dialogue
    • So, are you going to—
    • Dostoyevsky was mad for the em dash. About a quarter of Crime and Punishment is em dashes. [Again, not really. I only read half of it, so I can’t verify this.] [MD: Ahem. ‘I only read one-third of it’ might be a more accurate statement. Just saying.]

The en dash is used:

  • to show a range, or span
    • She’s working 9–5, just trying to make a living…
    • The Sydney–Brisbane flight has been delayed. Here’s a complimentary $15 voucher that you can use to buy a thimble of beer and half a packet of peanuts while you wait for the next 3 hours.
  • to connect the 2 parts of compound modifiers when each part retains its own identity
    • The plan for the Australia–New Zealand railway was, some say, ill-conceived.
  • in place of a hyphen when what’s being hyphenated contains an open compound modifier on at least one side
    • The Jim Henson–designed theatre was lacking in leg room.

There are other types of dash, but nobody really cares about them except typesetters and ASCII-art aficionados…

To make these dashes in your own home (or workplace… or out and about):

  • on Mac
    • em dash—hold option + shift then press [minus sign]
    • en dash—hold option then press  [minus sign]
  • on PC
    • global Windows shortcuts
      • em dash—hold alt and type 0151 on the numerical keypad
      • en dash—hold alt and type 0150 on the numerical keypad
        • This is easy to remember because the numbers are the same as those used in the numerical HTML special character code &0150; (or –) and &0151; (or —). Shut up. It’s not weird that I know that.
    • in Microsoft Office
      • em dash—hold ctrl + alt and press [minus sign] on the numerical keypad
      • en dash—ctrl and press  [minus sign] on the numerical keypad
  • in Linux
    • If you’re using Linux, you are a super geek and already know how to do this.