Dashes come in three sizes: small, medium, and large. But you can’t just order up whatever size you feel like. Each dash must be cooked to order.
For a lot of us, dashes are a secret menu, available only to those in the know. We think good writing should be like good cooking: available to everyone. So let’s take a look inside the kitchen.
The hyphen often becomes the de facto dash when a writer isn’t aware that other dashes are available and required. The hyphen should generally only be used when fusing two words into one entity. For example, you would use a hyphen between “mother,” “in,” and “law” in the sentence “Remind me to buy aspirin before my mother-in-law arrives.”
Hyphens are also generally used in compound adjectives when they come before the noun. You’d write, “My off-campus apartment is a dump” and “My dumpy apartment is off campus.” Compound adjectives get tricky, so it’s best to look up the word in a dictionary or style guide. And be aware that adverbs ending in –ly don’t get hyphenated.
En Dash (Medium)
An en dash is used to indicate a range, whether it’s dates, times, pages, distances, etc. This is where hyphens often get wrongly deployed. It’s not “August – December, “ but rather “August – December.” Likewise, it’s “pages 34 – 78,” not “pages 34-78.”
How can you order up an en dash? In Microsoft Word, type the first word (or number), hit space, type two hyphens, hit space, write the second word (or number), and then hit space again. The software should automatically transform the two hyphens into an en dash.
Em Dash (Large)
The em dash is the largest of the three, spanning the width of the capitalized letter “M” just as the en dash spans the width of “N.” Use the em dash to emphasize something or to bracket off a parenthetical statement. “At their wedding reception, they served shrimp cocktails, bruschetta—and White Castles!”
The em dash is used for dramatic effect, which can generally be reined in by replacing it with a comma, parentheses, or a colon depending on the particular sentence. That’s why employment of the em dash is largely a personal matter. Use sparingly and intentionally. Overuse will be grating to many readers.
To get your hands on an em dash, you follow the same procedure to get the en dash, but without the spaces on either side of the two hyphens. First word, two hyphens, second word, space will tell the software to transform the hyphens into an em dash.
Now get to cooking!