The em dash has been around since the time of Gutenberg, but there is no doubt that its heyday has arrived. It reigns triumphant among punctuation marks, spattered prominently across books, web pages, and more.
No one really knows what quirk of the human mind has led to the adoption and ultimate overuse of the em dash. Perhaps it truly is a symptom of an era with a short attention span, as some have suggested. Or perhaps another theory is correct and the em dash owes its prominence to its nonthreatening appearance.
Of course, there is nothing wrong with using the em dash—in its proper place. But how does one decide what that proper place is? The experts are not always in agreement on the subject, but there are a few uses that are routinely accepted.
When to Use an Em Dash
- To precede a quote attribution:
Early to Bed and early to rise,
Makes a Man healthy, wealthy, and wise.
- To set off a series in order to avoid excessive use of commas:
When he breakfasted or dined all the resources of the club—its kitchens and pantries, its buttery and dairy—aided to crowd his table with their most succulent stores….
—Jules Verne, Around the World in Eighty Days
- To indicate an abrupt pause, interruption, or change of thought:
“…My spirit never walked beyond our counting-house—mark me!—in life my spirit never roved beyond the narrow limits of our money-changing hole; and weary journeys lie before me!”
—Charles Dickens, A Christmas Carol
- To set off a word or phrase for emphasis:
The rear axle began to make a noise—a grinding, chattering, teeth-gritting rasp.
—William Strunk Jr. and E.B. White, The Elements of Style
When Not to Use an Em Dash
Obviously, then, the trouble with the em dash is not its frequent use, but its frequent abuse.
One common issue with the em dash is that it can be confused with the hyphen and the en dash. Although these punctuation marks look similar, they have very different roles:
- Em dash (—): Uses explained above.
- En dash (–): Used to connect ranges of numbers (grades K–3), link names (American–Mexican border), and substitute for hyphens in open compounds (pre–Cold War years).
- Hyphen (-): Used to link words (noble-minded man) and parts of words, such as at the end of a line.
Another problem is that today the dash is decidedly overused. Writers tend to forget that they have other tools in their toolbox and pull out an em dash at every opportunity. Unfortunately, overuse of any type of punctuation mark is tedious and distracting. Furthermore, the very nature of the em dash is to break things up a bit. Too many breaks, pauses, starts, and stops can ruin the cohesiveness of a sentence or paragraph.
To avoid falling into this common error, a writer should spend a little time developing a well-filled punctuation toolbox.
Up Next: Em Dash Use and the Alternatives
- Just for fun, find the first three sets of em dashes in A Christmas Carol by Charles Dickens. Dickens loved to use em dashes for a variety of reasons—all his own—in all types of cases. So knowing in advance you’ll be hard pressed to apply hard-and-fast rules here, which of the four reasons to use an em dash listed above could you apply to those first three sets? To make them easy to find, just do a search in your browser and in the search box enter 0151 on your keypad while holding down Fn+Alt. (Our stab at answers below.)
- Emily Dickinson was known for her em dash use. Read “The Railway Train.” How is the em dash used in this case?
Hyphens, En Dashes, Em Dashes
Rules from the Chicago Manual of Style. Note that CMOS does not use spaces on either side of an em dash, the AP style does.
Answers to questions above:
From The Christmas Carol by Charles Dickens (your answers may vary!):
- say Saint Paul’s Churchyard for instance—excessive comma use (count the number of commas in that sentence already)
- of all the good days in the year, on Christmas Eve—emphasis (the fact that it is Christmas Eve is rather crucial to the story).
- it had not been light all day—interruption
Emily Dickinson uses the em dash for emphasis in the poem “The Railway Train.”