What Words Should be Hyphenated?

A hyphen is a bit of punctuation used to join two (or more) different words. Some hyphen usage is determined by your style, but style guides generally recommend using a hyphen if it makes your sentence easier to understand.

There are six situations in which you should use a hyphen between words:

• when using a compound adjective before a noun

• when stating age before a noun

• when typing out numbers twenty-one to ninety-nine

• when using certain prefixes

• when you need to improve clarity

• when using a compound modifier before a noun
  
  Let’s look at each situation in more detail and with examples.

Compound Adjectives and Nouns

When you use a compound adjective before the noun, you should hyphenate:

• there’s off-street parking here

• chocolate-covered raisins

• this is a family-owned business

• small-town charm

When compound modifiers come after the noun, you don’t need to hyphenate:

• parking here is off street

• raisins are chocolate covered

• this business is family owned

• charm of a small town

Trigrams as Compound Modifiers Before a Noun

Trigrams are sets of three words that are hyphenated.

When you use three words together as a single thought describing or modifying a noun and you put them before the noun, you should hyphenate them:

• It was a matter-of-fact decision.

There are certain trigrams that are always hyphenated, like one-on-one.

Age and Nouns

If age is being used as an adjective before the noun, you should hyphenate:

• The five-year-old boy is ready for school.

• The toddler is a two-year-old terror.

But if the age comes after a noun or verb, you don’t hyphenate it:

• The boy is five years old.

• The terrifying toddler is two years old.

Numbers 21 Through 99

You need a hyphen when writing out numbers twenty-one and ninety-nine, and everything between.

Hyphenated Prefixes

Normally, prefixes don’t need hyphens, but they do when the word is a proper noun:

• Place your order pre-Christmas to enjoy our discount.

• We’ve seen a rise in non-American films recently.

Different style guides recommend using a hyphen with different prefixes, and sometimes they specify limitations on when a hyphen would be used with a prefix. For example, the Associated Press style guide recommends a hyphen after the prefix pro- only if it’s used to show support for something.

You generally need hyphens with the prefixes self-, ex-, and cross-:

• I’m a self-motivated person.

• We’ve decided to honor the ex-servicemen at our next party.

• I want to cross-examine the witness.

Hyphens Used to Improve Clarity

Hyphens can be used to clarify confusing or awkward combinations, like “shell-like” or “de-ice.”

You can also use a hyphen to prevent misunderstanding of your sentence meaning:

• I wanted to re-create the same dance as last time.

• We’re going to recreate at the spa this afternoon.

How to Use a Hyphen After an Adverb

When a hyphen connects an adverb and an adjective (e.g., well-dressed), it is known as a compound modifier. Compound modifiers describe the noun that follows with greater precision. But hyphens don’t always come after an adverb and adjective. When the adverb ends in -ly, it needs no hyphen (e.g., highly regarded). If the adverb and adjective follow the noun instead of preceding it, you can also leave off the hyphen.

We use adverbs to modify or describe words such as verbs, adjectives, and other adverbs. We can also create compound modifiers by linking an adverb and adjective to describe a noun. In many cases, we use a hyphen to link these two words:

• a well-dressed man

• my brown-eyed girl

• the best-designed robot

However, many adverbs end with the suffix -ly. When using these adverbs to create a compound modifier, do not use a hyphen:

• a highly regarded study

• the dimly lit study

• the barely worn dress

Another adverb that doesn’t need a hyphen is very. Treat very like an -ly adjective. She is a very tired girl, not a very-tired girl. Also, remember that some -ly words are not adverbs. You will still use a hyphen if the first word is not an adverb:

• a family-minded man

• supply-side economics

The rules change when the compound modifier follows the noun. Different style guides have different rules about hyphens when the compound modifier is later in the sentence. For instance, the Chicago Manual of Style would say the man was well read. The Associated Press style guide says that modifiers with well should always be hyphenated. In that instance, the correct phrase would be the man was well-read. Always check your required style guide for more details.