As a proofreader and editor, I encounter dashes on a daily basis. Many writers like to use them—for better or for worse—liberally in their work. But the mark also tends to cause confusion: What is the right way to use a dash?
There are actually two different types of dashes: an en (–) dash and an em (—) dash. The em dash is the longer of the two and is usually what people mean when they use the term “dash.” The en dash is shorter and often confused with the em dash.
Why are they called em and en dashes?
You can thank the printing industry for these names. Back when newspapers were set with type blocks, an em dash was approximately the same width as a capital letter M. Similarly, an en dash was about the same width as a capital letter N.
When should I use an em dash?
There are several ways you can use an em dash in your writing:
- To signal an abrupt change in thought
She wondered—as she often did—how any parent made it through the day without coffee.
- To set off a series within a phrase
All of the essentials—coffee, chocolate, and wine—were in her shopping cart.
- To add emphasis
The caffeine-addicted crowd inside the store became frantic—Starbucks was out of coffee.
Notice that when you use em dashes to signal an abrupt change in thought or set off a series, the sentence still makes sense if you remove the words inside the dashes. This is a good way to check and see if the dashes are in the right place in your sentence.
She wondered how any parent made it through the day without coffee.
All of the essentials were in her shopping cart.
Should I use a space on either side of the em dash?
Most examples that I see do not have a space on either side of the em dash. One notable exception, however, is The Associated Press. Their stylebook calls for a space on either side of an em dash in a sentence.
Her shoe collection — 700 pairs — consumed the entire basement.
If you are writing for a business, be sure you know the in-house style guidelines for using dashes and apply them accordingly.
When should I use an en dash?
En dashes can be used to indicate a range or length of time:
The program is appropriate for children ages 5–9.
The children took a nap every day from 1–3 p.m.
Again, The Associated Press colors outside the lines here by not using en dashes at all, ever. If this is your in-house style, take note.
What about hyphens?
Hyphens (-) are joiners. They are used to create compound modifiers, spell out numbers, and form compound words. For example:
- Caffeine-addicted crowd
The Associated Press uses hyphens in time and date ranges instead of an en dash:
The program is appropriate for children ages 5-9.
The children took a nap every day from 1-3 p.m.
Despite this variance by the AP, it should be noted that the hyphen, en dash, and em dash are not interchangeable. They each have their own role to play in good writing.
Deploy your dashes with discernment.
Dashes are an excellent alternative to many punctuation marks, including parentheses and commas. They help convey a less formal tone in writing, and can also add strength and emphasis to a sentence. However, there’s no need to dazzle your reader with an abundance of dashes. Master the use of this punctuation mark and the result will be a punchy paragraph with emphasis in all the right places. Too many dashes, however, will make your reader wonder—justifiably—whether you really know what you are doing.