The em-dash (—) is one of the two types of dashes used in punctuation, the other being the en-dash (–). The em-dash is the widest dash, and is also much wider than the hyphen. The em-dash is named after the letter ‘m’, as the em-dash is the same length as that letter. The em-dash can be seen in use below:
A vegetarian should not holiday in France—every meal has meat in it.
All explorers want to discover the unknown—some even get there—but it is easier said than done.
Similarly to the en-dash, the em-dash should only be used to separate a sentence when there is an interruption that breaks the flow.
Spacing and the em-dash
The em-dash should have no spacing on either side of it. This is the opposite of the en-dash, which requires a space on either side..
The em-dash versus the en-dash
Which type of dash should you use? People disagree regarding which is the best to use, but while the em-dash used to be the dominant type, the en-dash has now taken over as the most popular. Critics say that the em-dash looks heavier and less clean than the en-dash. They can be compared side-by-side below:
en-dash: We went to visit the Tower of London – and met a ghost.
em-dash: We went to visit the Tower of London—and met a ghost.
How to make an em-dash on the keyboard
The hyphen is easy to find on the keyboard, but it’s more tricky to find the em-dash. This results in many people using a double hyphen instead (–).
The em-dash can be created on the PC by using holding down the ALT key and typing 0151 on the numeric keypad. Only the numbers on the right hand keypad do this, not the numbers above the letters.
On the Mac, press Shift-Option and the minus key to make en em-dash.
You can use — in HTML to add the em-dash to a website.
Microsoft Word automatically converts two hyphens into a em-dash if you type a word after before and after. You can also add one through the selecting insert>symbol> and then choosing from the list of symbols.