When To Use a Hyphen
Confession time: While I wrote an impassioned and self-righteous blog on one famously misunderstood punctuation mark—the semicolon—I was being a hypocrite. While pretending to be a grammar expert, I had no idea how to use a hyphen.
If I use a hyphen, there is a 50/50 chance that Grammarly will call me out. And I have more Google searches on whether or not certain words are hyphenated than I'd like to admit.
As a professional writer, this could not stand. So, I did a deep dive into hyphenation rules so our clients could rest easy. Unfortunately, hyphen rules were as complicated as I feared, so after wading through many, many articles, I wanted to share the most important rules I learned.
In This Article:
Hyphen vs. Dashes
To clear up any confusion, I'll quickly explain the difference between a hyphen, an en dash, and an em dash.
Hyphen vs. En dash
Let’s be fully honest: the only difference between a hyphen (-) and an en dash (–) is about a millimeter and what you call it.
Technically, you use en dashes for date ranges (i.e., 1775–1783) or time ranges (9 a.m.–5 p.m.). If you want to go above and beyond, you can use option + (-) on Mac or Alt + 0150 on a numeric keypad for Windows. Or you can always use the special characters menu. But let's be real, no one will think worse of you for just using a dash.
Hyphen vs. Em dash
There is a more distinct usage difference between hyphens and em dashes because em dashes have a different grammatical function: they can replace a colon or comma.
Examples
I know that colons and em dashes can seem complicated, but they follow a simple rule—they introduce another clause.
When you’re writing an aside—that thing you can do to talk directly to the audience—you can use an em dash to set off that part of the sentence.
Em dashes can fill the spots of several other punctuation marks—colons, commas, and ellipses—with elegance.
A simple hyphen cannot do the job of an em dash. But luckily, you can quickly type an em dash out by pressing the hyphen key twice to let it auto-correct.
Hyphen Rule 1: A Gimme
Luckily for you and me, word processors now handle our first hyphenation rule: word division at the end of a line. Back in ye olden days, when you used a typewriter and ran out of space at the end of a line, you had an important decision to make: where to cut up the word. Microsoft Word and Google docs will handle that one for you now, so consider yourself lucky.
For the typewriter diehards or completionists, there are a couple of guidelines:
Never divide a one-syllable word
Divide words on a syllable
Use the built-in hyphen to divide compound words
Don't divide words where only one letter (or a two-letter suffix) is left on the line.
And that's that! You can feel good about yourself and will probably never have to use this one. Now, onto the less easy stuff.
Rule 2: Prefixes and Suffixes
Now, we're getting into the weeds of hyphenation. Prefixes are additions to root words at the beginning and suffixes at the end. And—I’m sorry to say—they are hyphenated sometimes. Luckily, the rule list isn't too long.
With prefixes, use a hyphen…
To avoid ambiguity:
Re-sign (to sign again) vs. resign (to quit a job)
When the prefix ends in a vowel, and the root word begins with the same vowel:
Co-operate (instead of cooperate)
Pre-existing (instead of preexisting)
With some prefixes like all-, ex-, and self-:
All-knowing
Ex-president
Self-esteem
When the root word is capitalized:
Anti-American
Pre-Renaissance
With suffixes, use a hyphen…
To avoid ambiguity or misreading:
Run-in (a quarrel or conflict) vs. run in (to enter quickly)
When the suffix begins with the same letter as the end of the root word:
Shell-like (instead of shelllike)
With some suffixes like -elect, -odd, and -in-law:
President-elect
Father-in-law
Five-odd (approximately five)
Rule 3: Compound Adjectives
Adjectives—refer to the School House Rock song if you need a refresher—are flexible parts of speech. You can pile up a whole mess of them before a noun to more exactly describe it. And you can use what are known as compound adjectives, where multiple adjectives come together to form a single concept.
You can quickly see if something is a compound adjective by putting a comma between the words. If it sounds dumb with a comma, congratulations–you found a compound adjective! Example: short-term memory vs. short, term memory.
And much like prefixes and suffixes, you hyphenate compound adjectives sometimes.
1. Compound Adjectives Before Nouns
Hyphenate compound adjectives when they appear before a noun they modify.
Example: a well-known author, a high-quality product.
2. Do Not Hyphenate Compound Adjectives After Nouns
Do not hyphenate compound adjectives when they appear after the noun they modify.
Example: The author is well known. The product is high quality.
3. Adverbs Ending in -ly
Do not hyphenate compound adjectives when the first word is an adverb ending in -ly.
Example: a beautifully designed room, a highly respected scientist.
4. Fractions and Numbers
Hyphenate fractions and compound numbers when they modify a noun.
Example: a two-thirds majority, a ninety-nine-year-old man.
5. Clarity and Avoiding Ambiguity
Use hyphens to avoid confusion or ambiguity.
Example: a fast-moving car (a car that moves quickly) vs. a fast moving car (a moving car that is fast).
Exceptions
Some compounds are permanently hyphenated, as listed in dictionaries (e.g., mother-in-law, well-being).
Chaos: Compound Nouns
Despite what your English teacher would have you believe, English is not a perfect and fixed language. When two words are combined to become a noun, the powers that be have not agreed on exactly how those should be punctuated. There are inconsistencies between dictionaries about many compound words.
"Ebook" is a good example. A mash-up of electronic and book, some businesses religiously hyphenate it as "e-book." In contrast, others use "ebook" (technically, you could also use "e book").
That's when having a style guide becomes essential. Businesses need to project a united front when creating a brand image. You want to ensure your language is consistent and reliable so people know your business is, too.
Since you probably don't want to go through the entire English language for your style guide, my advice is to pick one—AP style, Chicago, etc.—and then create a short list of words your business often uses for quick reference.
Here’s an excerpt from our list for reference:
Cell phone (noun) - Two words, no hyphen
Clickthrough (noun) - One word, no hyphen
e.g., My clickthrough rates are up thanks to the amazing SEO advice I received from People First Content!
Why did we decide on these? I have no idea! Whether for aesthetic purposes or pure instinct, it really doesn’t matter what your brand-specific rules are as long as they’re consistent.
Stay Hyphenating
While this is by no means a comprehensive guide to hyphenation, it's enough to get you 90% of the way there. I got to correct Grammarly this time, which felt good. If there's anything you should take away, it's how important having a brand style guide is. Hyphenation is up for debate, but your brand image should be cohesive. If you don't have a style guide, we have one you can download and customize for free! Just put your info in below, and it'll show up in your inbox.
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