How to properly use and format hyphens and dashes

The em-dash (—) is getting a lot bad press these days. Writers overuse it, and not coincidentally, so do AI language generators.

An em-dash is a perfectly reasonable piece of punctuation, but if you’re going to use it, you might need a little more detail on when and how. So here’s a tutorial on the three kinds of dashes — hyphens, em dashes, and en dashes — including how type them and how to render them in formal page layout, as in a book.

When to use a hyphen

You can use three kinds of dashes in writing. One is the lowly hyphen (-), typed with the hyphen/underscore key just to the right of the zero on your keyboard. Use the hyphen for compound words like mother-in-law and nitty-gritty. It’s also appropriate when hyphenating words broken at the end of a line: your word processing or layout software will take care of that for you.

Less well understood is the use of hyphens in compound adjectives, for example 800-pound gorilla or blue-collar worker. In the latter case, the reason for the hyphen is to eliminate ambiguity in what the adjective modifies (the collar is blue, not the worker). You don’t need to use the hyphen when an adverb precedes and modifies the adjective, for example, highly annoying drivel.

Hyphens in compound words have tended to disappear over time. We used to write e-mail, on-line, and anti-viral; now we write email, online, and antiviral. Style guides track these shifts and will occasionally declare that you no longer need a hyphen in a word that used to have one.

Always use a hyphen in contexts where it functions as part of a piece of text recognized by a computer, such as in email addresses, web addresses, and computer code. Using one of the other types of dashes in those contexts would potentially introduce errors.

In typeset text, there are no spaces between hyphens and the words they connect. “Top-down management” should never be “top – down” or “top- down.”

When to use an em-dash

An em dash is a longer dash, typically the width of a lowercase letter “m.”

You can type an em dash directly typing Shift-Option-hyphen on a Mac or Alt-0151 on a PC. There are other shortcuts in other programs. For example, in Microsoft Word, if you type two hyphens followed by another word, the software will change it to an em dash as soon as you hit the space after the following word. And if you’re writing in WordPress, it converts two hyphens to an em dash when it displays the post. So many writers have gotten used to typing two hyphens whenever they want an em dash to appear.

Use an em dash to indicate a pause in text. But as the meme at the start of this post indicates, people tend to get carried away with em dashes and just throw them into text when they could use a different punctuation mark.

As I wrote the last time I covered this topic:

Two sentences that stand on their own deserve their own endings — just use a period. As shown below — see how much better it reads?

Two sentences that stand on their own deserve their own endings. Just use a period.

Don’t be afraid to use a semicolon — it’s effective for two loosely connected sentences, as shown below:

Don’t be afraid to use a semicolon; it’s effective for two loosely connected sentences.

Interpolated, interrupting phrases — such as this one — are fine with commas, especially if they’re not too long; if they’re longer — and from my experience, sometimes they’re more of an extended ramble than an interrupting phrase — fearlessly use parentheses. Or — you could try this — just take the silly phrase out altogether.

Interpolated, interrupting phrases, such as this one, are fine with commas, especially if they’re not too long; if they’re longer (and from my experience, sometimes they’re more of an extended ramble than an interrupting phrase) fearlessly use parentheses. Or just take the silly phrase out altogether.

As for the dash at the end of a sentences, an ellipsis is more effective if you’re indicating something trailing off —

As for the dash at the end of a sentence, an ellipsis is more effective if you’re indicating something trailing off . . . .

Text that’s full of em dashes tends to look spidery and distracting when laid out on the page. It also makes for herky-jerky reading. And, justly or not, it makes people suspicious that they’re reading AI-generated text. So replace em-dashes with other punctuation when possible.

Style guides disagree on the rendering of em dashes. AP style suggests spaces, while Chicago Manual of Style and academic style guides say no spaces. Whatever you do, be consistent.

When to use an en dash

The en dash is an obscure creature, longer than the hyphen and shorter than the em dash. You can type it with Option-hyphen on a Mac or Alt-0150 on a PC.

It has some very specific uses. These include in ranges of numbers (pages 25–40), as a minus sign in arithmetical expressions, and in compound adjectives that use more than one word (“United Kingdom–based”).

Some book typesetters will use an en dash surrounded by spaces where the rest of use would use an em dash. That is, instead of:

He wrote — horrors — every sentence in passive voice.

You’ll read:

He wrote – horrors – every sentence in passive voice.

The publisher for a book I recently ghostwrote rendered all the dashes this way. This bedeviled both my proofreader and me, since we were expecting em dashes as in every other book we’d been involved with. Worse, the publisher had inconsistently used em dashes in a few places, likely where a different design professional in the same organization had followed their own instincts. But I took the decision to the author client and he preferred the text with en dashes surrounded by spaces, just as the publisher had rendered it. Does this look okay to you, or weird?

So . . .

Don’t use an em dash when another punctuation mark would do.

And in typeset text, be consistent on use of en or em dashes for pauses, and on whether you include spaces on either side.

And keep your paws (pause?) off my dashes, AI. I’m not giving them up just because you use too many of them.