What is an em dash?
The em dash is an incredibly versatile punctuation mark that can be used instead of parentheses, commas, colons, or quotation marks in a sentence. The em dash (—) sets off a word or clause and adds emphasis. Or, it can signal an interruption (see our article on interrupting sentences for more on that!) or amplification (“expanding”) of an idea. It’s also the longest of the dashes (hyphen, en dash).
Why is it called em dash?
The name comes from typography—the work of setting, arranging, and printing types. An em dash is a dash that is the width of an M.
How do you type an em dash?
The hyphen, double hyphen, and minus sign are encroaching on the territory of the em dash with increasing frequency in recent years. In the massive digitization project, Google Books treats hyphens, en dashes, and em dashes as the same character, translating them all into “–.” Neither the en nor the em appear on standard keyboards, making them even harder to use.
So, how do you type an em dash? On a mac, use “option + shift + -“. On a PC, use “Alt + Ctrl + -“.
Most newspapers (which follow The Associated Press Stylebook) add a space on either side of it. Many other style guides opt not to add the spaces. If you’re not using a style guide, the most important thing is to be consistent throughout your work.
How do you use an em dash?
1. To join independent clauses
The em dash can join two independent clauses in place of a semicolon. People use it instead of a semicolon more often these days because it can provide a more casual tone and look. Here’s an older example from The Adventures of Huckleberry Finn: “Well, nobody could think of anything to do—everybody was stumped, and set still.”
It can also replace a colon when introducing phrases, clauses, or examples. This can either soften the sentence or add color, as in this example from The Tragedy of Pudd’nhead Wilson: “Each person is born to one possession which out-values all his others—his last breath.”
2. To substitute for unknowns
The em dash has another job. It can substitute for an unknown element, like a missing word or letter. Typically, two em dashes represent the absence of one or more letters in a word. Three em dashes indicate the absence of an entire word. This format is often used in bibliographies when citing multiple works by the same author. It can also show a lack of clarity in transcripts. And now, it can even represent swear words (Here’s more on symbolic swears, in case you’re curious)!
3. To give stylistic choices
A lot of writers have adapted the em dash to suit their own purposes. James Joyce used the em dash (rather than quotation marks) throughout Ulysses. Emily Dickinson used em dashes (rather than commas) in most of her poetry. These uses are mainly personal style choices.
4. To add a casual tone
Em dashes are also used as interruptors in sentences, mostly in blogs and digital content. This adds a casual and conversational tone that readers enjoy, especially when reading online. You can use em dashes to insert commentary on what is written, to add a small joke or witty comment, or to add an example to make what is written more relatable.