Hyphen: A Simple Guide to Rules and Usage

Hyphens join related words together in a sentence, such as in father-in-law, five-year-old and sugar-free. They prevent misunderstandings and clarify writing. But when should you use a hyphen — and is a hyphen the same thing as a dash? Find out when a hyphen is necessary, when it’s optional, and when you don’t need one at all.

Examples of hyphenated words in sentences Examples of hyphenated words in sentences
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When To Use a Hyphen

You can find the hyphen symbol (-) on your keyboard, typically at the end of your number row near the zero (0) key. There are several occasions when you need to use a hyphen to be grammatically correct.

How To Use Hyphens in Compound Words

Combining two words makes a completely different word known as a compound word. Most compound words don’t need a hyphen, but in some cases, they do. For example:

Use a Hyphen

Hyphen Examples

when compound adjectives come before nouns

grass-fed beef
dog-friendly campground
ten-dollar bill

with compound words that aren’t combined

editor-in-chief
brother-in-law
six-pack

You may see these rules in sentences like:

  • The two-hour class is almost over.
  • It’s a good idea to avoid lead-based paints if possible.
  • Recess became a free-for-all once it started raining.
  • This article about healthy eating is a real eye-opener.

How To Use Hyphens With Prefixes and Suffixes

Most of the time, adding affixes to a word doesn’t require a hyphen. In some cases, however, it’s a good idea to hyphenate the prefix or suffix to its base word, including: 

Use a Hyphen

Hyphen Examples

prefixes self-, all-, and ex-

self-esteem
all-inclusive
ex-girlfriend

prefixes and a noun that share a letter

re-energize
meta-analysis
anti-inflammatory

prefixes before proper nouns or adjectives

un-American
mid-April
post-Renaissance

suffixes -elect and -odd

mayor-elect
president-elect
twenty-odd

suffixes with three-syllable nouns (or more)

adobe-like
vegetable-based
homecoming-ready

when a noun and a suffix share a letter

Moab-bound
shell-like
window-wide

Examples of these hyphen rules in a sentence include:

  • Bullying can negatively affect teenagers’ self-esteem. (Hyphenate self-)
  • My children believe I am all-knowing. (Hyphenate all-)
  • Do you know my ex-husband? (Hyphenate ex-)
  • Let’s conduct a meta-analysis of the research. (Hyphenate when prefix and word share a letter)
  • That is a beautiful pre-Raphaelite painting. (Hyphenate when prefix comes before a proper noun or adjective)
  • There will be thirty-odd kids at the party. (Hyphenate suffix -odd)
  • I love these restaurant-style tortilla chips. (Hyphenate suffix when noun has three or more syllables)
  • The pitcher has a drip-proof lid. (Hyphenate when suffix and word share a letter)
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Other Times To Use a Hyphen

You’ll want to use a hyphen in a few additional situations. Compound numbers (numbers 21-99) and fractions always require hyphens when written out. It’s also a good idea to include a hyphen when the unhyphenated version of the word is a completely different word (such as prefix, as in “a word placed in front of another” and pre-fix, as in “before a fix”). For example:

Use a Hyphen

Hyphen Examples

with compound numbers (21-99)

forty-seven
sixty-six
ninety-one

with fractions (except one half)

two-thirds
three-fifths
nine-tenths

to avoid confusion

re-pair (to pair again, not “repair”)
re-sign (to sign again, not “resign”)
un-Earth (not from Earth, not “unearth”)

Examples of these hyphen rules in sentences include:

  • The car was going fifty-five miles per hour. (Hyphenate compound numbers)
  • Sheryl bought twenty-eight pencil boxes. (Hyphenate compound numbers)
  • One-third of freshmen stayed in the dorms. (Hyphenate fractions)
  • The kids ate three-quarters of the pizza. (Hyphenate fractions)
  • I re-sent the letter. (Not resent)
  • Most of the fans in the stadium are pro-State. (Not prostate)

When Not To Use a Hyphen

It seems like using a hyphen is often the safe choice in writing. Generally, that’s true — although there are a few times when you shouldn’t use hyphens. These occasions include:

  • when a compound adjective follows the noun (“the well-known artist” vs. “the artist is well known”
  • when an adverb ending in -ly modifies a noun (“the happily singing children”)
  • when using most prefixes or adjectives (countrywide, nondairy, untouched)
  • in closed compound words (lighthouse, firefighter, keyboard)
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When To Use a Dash Instead of a Hyphen

Many people confuse hyphens and dashes because they look similar in printing. However, they serve very different purposes.

  • Hyphens (-) connect words and parts of words, and aren’t separated by spaces.
  • Dashes, (–) and (—), indicate ranges or pauses in writing, and are usually separated by spaces.

The common rule of thumb is to use a dash when showing a break in the text, a range in dates or time. Use a hyphen to create a connection between two words.