I have had a lot of people tell me they don’t know the difference between a hyphen, an en dash, and an em dash, so here’s my first post in a while. (And I apologize for not posting lately. I’ve been so focused on writing my books and freelancing that I’ve barely had time to tend to my blog and my podcast.) And yes, there are distinct differences in the usage of these three dashes, and they are not to be used interchangeably. After telling me I singlehandedly taught him how to use an em dash, I told someone at the company I freelance for, “I have a love for the em dash the way some writers swoon over the Oxford comma.” And don’t get me wrong—I’m a sucker for the Oxford comma—but I love my em dashes.

In short, a hyphen (-) is used to join words or parts of a word. For example: father-in-law. The hyphen is the shortest of the dashes.
The en dash (–) is the second shortest dash, and it is used to show ranges of numbers or as a “super” hyphen in words that are not easily hyphenated. To type an en dash on a Mac, hold down the Option button and hit the hyphen button. If you’re on a PC, hold down the Alt button and type 0150 on your numeric keypad.
The em dash (—) is used to connect thoughts or show a pause in thought. It’s a highly versatile dash, and you’ll see it a lot in fiction. Think of it as stronger than a comma, but not as strong as a period or semicolon. (“She was wearing a blouse—the blue one that I loved on her—and she tugged at the hem while inspecting her reflection in the mirror.”) To type an em dash on a Mac, hold down Option, Shift, and press the hyphen key. If you’re on a PC, hold down Alt while typing 0151 on a numeric keypad.
The hyphen and the en dash are fairly straightforward, but there tends to be some confusion over how to properly utilize the em dash in fiction.
In Chicago Manual of Style, the em dash has no spaces around it. There is, however, some confusion over how to properly use em dashes around dialogue. Here are a couple of examples to show you how it’s done:
Example 1 (Showing someone’s speech as being interrupted by another speaker)
“No, you don’t understand. I—”
“I understand perfectly,” she snapped, her face flushed. “You just want to sleep with other women.”
Example 2 (Showing action within dialogue)
“It’s fine. It’s all fine. It’s perfectly”—he wiped a hand over his face, which was damp with sweat—”fine. All fine.”
In Example 2, notice that the action in between the dialogue is not capitalized or punctuated in any way other than the em dashes. Note that if you have a straight dialogue tag in between your dialogue, it’s fine to use commas. Example:
“That’s not,” she said, “what we agreed on.”
I apologize for the short post, but I’m gearing up for NaNoWriMo (National Novel Writing Month), so if anyone wants to be buddies on nanowrimo.org, feel free to add me (AlliWill). Also, just a reminder that my latest release, The Sound of Snap Dragons (Book 1 in The Sound Series: The Kylie Bell Chronicles), is available on Amazon and Barnes and Noble!