Hyphen (-) | Rules of Correct Punctuation
A hyphen (-) is a punctuation mark used to connect two or more words (or parts of words) to show that they form one unit of sense—e.g., “fast-paced,” “shake-up,” “four-year-old,” “post-punk.”
Mistakes with hyphens are very common: leaving them out when they’re needed, adding them when they’re unnecessary, or putting them in the wrong place. This is mainly because the same series of words may be hyphenated or not depending on the role it plays in a sentence.
This table covers the main guidelines for using hyphens correctly, which are then explained in more detail below.
|Hyphenate …||Don’t hyphenate …|
|Compound adjectives that come before the noun: “well-known rules”||Compound adjectives that appear after the noun: “The rules are well known.”|
|Phrasal verbs used as nouns: “There’s been a break-in!”||Phrasal verbs used as verbs: “The burglar broke in through the skylight.”|
|Some compound nouns, especially if more than two words (check a dictionary): “brother-in-law,” “jack-of-all-trades”||Most compound nouns: “high school,” “business owner,” “apple pie”|
|Prefixes connected with a numeral or capitalized word, or to avoid confusion with another word: “pre-Columbian,” “mid-1960s,” “re-pair” (meaning “pair again”)||Other prefixes generally: “predate,” “midcentury,” “repair”|
When to use a hyphen
A series of two or more words joined by hyphens is called a hyphenated compound. It’s one of three types of compound words, along with open compounds (written with spaces between the words: “high school”) and closed compounds (with no spaces or punctuation: “freshwater”).
Whether a specific compound should be hyphenated or not often depends on its grammatical role in the sentence. For example, “long term” isn’t hyphenated when it’s used as a noun (“in the long term, we …”) but it is when it’s used as an adjective modifying the noun that follows (“long-term considerations”).
The point of hyphenation is to show that two words are connected, especially when they might otherwise be read as separate concepts.
|The Quaker religion has a long standing tradition in its worship services.||A tradition of standing for a long time|
|Lighting candles is a long-standing tradition.||A tradition that has existed for a long time|
The hyphenation of specific word combinations changes over time, tending to move from open compound to hyphenated compound to closed compound as the term becomes more established (e.g., “to day,” “to-day,” “today”). The guidance on specific points can also vary between style guides.
There are several main contexts in which hyphenation may be needed:
Hyphenating compound adjectives
A compound adjective is a series of two or more words that is used to describe a noun. The individual words aren’t necessarily adjectives, but they collectively function as an adjective. The hyphenation of these phrases depends on their position in the sentence.
When a compound adjective appears in the attributive position (before the noun it modifies), it should be hyphenated. Make sure to hyphenate all the words that are part of the adjective—and not to hyphenate the noun itself.
When a compound adjective appears in the predicative position (after the noun, normally connected by a linking verb), it is typically not hyphenated. It may also be rephrased to read more clearly (e.g., “first-person narration” vs. “narration in the first person”).
|Attributive||Predicative or other phrasing|
|The VP for development, a well-respected economist, oversees the London-based company’s fast-paced expansion.||The VP is well respected, and her area of responsibility is fast paced. The company is based in London.|
|The low-profile activities of the agency have a huge influence on modern-day international politics.||In the modern day, John keeps a low profile.|
|For long-term operations, up-to-date records are essential.||Databases should be kept up to date. Accurate records are important in the long term.|
Compounds with participles
There is some disagreement between style guides about the hyphenation of compound adjectives that consist of an adjective or noun followed by a verb participle. This includes both past (e.g., “packed,” “proven,” “filled”) and present participles (e.g., “looking,” “inspiring”).
American style guides like Chicago and APA recommend hyphenating these combinations only when they are attributive and leaving them open otherwise (as with “fast paced” in the example from the previous section).
Meanwhile, British style authorities like Oxford tend to recommend always hyphenating this type of compound. In the previous example, Oxford style would recommend writing “her area of responsibility is fast-paced.”
|US style||UK style|
|Sanjay was very good looking but not especially quick witted.||Sanjay was very good-looking but not especially quick-witted.|
|The view is awe inspiring.||The view is awe-inspiring.|
Exception: Adverbs ending in “-ly”
Style guides tend to agree on one clear exception to the rule of hyphenating compound adjectives before the noun. When the first word of the compound is an adverb ending in “-ly,” no hyphen is needed. This applies whether the phrase appears before or after the noun.
The logic behind this exception is that no ambiguity is possible in such cases: the “-ly” ending already identifies the word as an adverb that will modify the following word, so adding a hyphen would be redundant.
- This is a highly-paid position at a company that is widely-renowned for its growth and vision.
- This is a highly paid position at a company that is widely renowned for its growth and vision.
Note that the exception doesn’t apply to other adverbs that don’t end in “-ly” (e.g., “well-read students”).
A similar exception generally applies to compounds starting with “more,” “most,” “less,” “least,” “fewer,” “fewest,” and “very.” In most cases, there’s no need to hyphenate these (e.g., “most valued,” “less important,” “very happy”). Do so only if there is some risk of confusion.
|The book with the most favorable reviews||“Most” and “favorable” both separately modify “reviews.” The book has the highest number of favorable reviews.|
|The book with the most-favorable reviews||“Most” modifies “favorable.” The book has the reviews (any number) that are the most favorable.|
Phrasal verbs used as nouns
A phrasal verb is a phrase consisting of two or more words (often a verb and a preposition) that functions collectively as a verb (i.e., describes an action or process). Examples include “log in,” “go ahead,” “start up,” and “look out for.”
These phrases are written without hyphens when used as verbs, but many of them are also commonly used as nouns with related meanings. When used as nouns, they are always either hyphenated or (if particularly well established) written as one word (e.g., “login”).
|Phrasal verbs||Used as nouns|
|The supervisor told him to go ahead with the experiment.||We got the go-ahead on the project.|
|The project will start up tomorrow.||The startup has only nine employees.|
|I don’t think I’ll be able to catch up to first place.||We’re playing catch-up with our competitors.|
|The government bailed out the bank.||The bailout was controversial.|
Don’t write phrasal verbs with a hyphen or as a single word when they are used as verbs. They should be written as separate words in such cases:
- Please go-ahead and setup your account.
- Please go ahead and set up your account.
Hyphenating compound nouns
The majority of compound nouns are written as open compounds with spaces between the words (e.g., “high school,” “house party,” “student nurse”).
Some well-established compound nouns are always written as closed compounds (e.g., “shipbuilding,” “schoolteacher”). And some, especially those consisting of a phrase of three or more words, are always hyphenated (e.g., “mother-in-law”).
Check out the examples below, and check a dictionary if you’re unsure how to write a specific term. If you can’t find a compound noun in the dictionary, write it with spaces by default.
|Open compounds||Hyphenated compounds||Closed compounds|
|artificial intelligence, attorney general, common sense, French fries, high school, house party, living room, roller coaster, search engine, theme park, walking stick||jack-of-all-trades, know-it-all, man-of-war, merry-go-round, runner-up, sister-in-law, stick-in-the-mud, well-being||backpack, boyfriend, breakfast, bypass, checkout, cheesecake, highway, newborn, payout, peanut, smartphone, weekend, wherewithal|
Prefixes and suffixes
A prefix is a term like “pre-,” “non-,” or “co-” that is added to the start of a word to alter its meaning. A suffix is the same thing but added to the end of a word (e.g., “-less,” “-able,” “-gram”).
In the vast majority of cases, words formed with prefixes or suffixes should be written as a single word, without hyphens (e.g., “transgender,” “nonnegotiable,” “faithless,” “catlike”).
There are a few cases where style guides normally recommend adding a hyphen, shown in the table below. If none of these situations applies, assume that no hyphen is needed.
|Use a hyphen …||Examples|
|With the prefix “self-”||self-aware, self-serving, self-sustaining|
|To separate two of the same vowel, repeated prefixes, or other letter combinations that could easily be misread||anti-intellectual, de-emphasize, meta-analysis, pro-life, sub-subentry, un-unionized|
|To attach a prefix to a numeral or capitalized word||post-1968, sub-Saharan, un-American|
|To avoid confusion with another word||co-op, re-form, re-cover (different from “coop,” “reform,” and “recover”)|
|To add a prefix to a term that already consists of multiple words||mid-first-century, non-self-sustaining, semi-self-obsessed|
|When a suffix is used in a new or unusual combination (not listed in the dictionary)||briefcase-less, pigeon-proof, TikTok-able|
Note that prefixes and suffixes can’t stand on their own as individual words, so there should not be a space between a prefix or suffix and the word it modifies.
- In the post war period, re construction efforts seemed end less.
- In the postwar period, reconstruction efforts seemed endless.
Common mistake: Hyphenation of ages
People are often unsure how to hyphenate phrases used to describe age, such as “four-year-old.” Keep in mind the following rules to get it right.
|When the phrase is used as a noun, hyphenate.||The seven-year-old greeted me.
Not many 75-year-olds can run a marathon.
You can’t leave a six-month-old to fend for herself!
|When the phrase is used as an adjective before a noun, hyphenate.||Mary’s seven-year-old son greeted me.
A 75-year-old woman is competing!
A six-month-old infant is highly dependent on its parents.
|When the phrase is used as an adjective after the noun, do not hyphenate. Note that the unit of time is pluralized in such cases (e.g., “years”), unless the number is one.||The child is one year old.
The winner was 75 years old.
My daughter is six months old.
Without proper hyphenation, your meaning is often unclear:
- Five year old girls: Are there five girls, or are the girls five years old?
- Five-year-old girls: The girls are five years old.
- Five year-old girls: There are five girls, all one year old.
Hyphen vs. dash
Don’t use a hyphen, with or without spaces, to indicate a parenthetical phrase or a break in a sentence. Use an em dash (—) with no spaces instead.
- It was no use‐I couldn’t get through to them.
- It was no use—I couldn’t get through to them.
- Dark, leafy greens ‐ such as spinach and kale‐ are an important part of a healthy diet.
- Dark, leafy greens—such as spinach and kale—are an important part of a healthy diet.
Don’t use a hyphen to indicate a range of numbers or to replace the word “to” in phrases indicating a relationship, journey, or score. Use an en dash (–) instead.
- Add 20-30 mg to the solution. Refrigerate and wait 10-15 minutes.
- Add 20–30 mg to the solution. Refrigerate and wait 10–15 minutes.
- After the team lost 4-1 at home, the South-North metro line was packed with rowdy fans.
- After the team lost 4–1 at home, the South–North metro line was packed with rowdy fans.
Capitalization of hyphenated terms
If a hyphenated term appears at the start of the sentence, capitalize only the first word, not the word(s) after the hyphen.
- Long-Term side effects have not been adequately investigated.
- Long-term side effects have not been adequately investigated.
Sometimes, though, a hyphenated compound needs to be capitalized because it’s used in a title. Modern style guides such as Chicago and APA recommend capitalizing the word(s) after the hyphens according to the same principles as other words in the title.
- Capitalize the first and last of the hyphenated words.
- Don’t capitalize any short conjunctions, articles, or prepositions that appear in the middle of a hyphenated term.
- In cases where a prefix or suffix is connected to a word by a hyphen, capitalize only the first part.
It used to be standard to capitalize only the first word and leave all subsequent words lowercase. Some style guides may still recommend this approach.
|Modern style||Old style|
|An Overview of Twenty-First-Century History||An Overview of Twenty-first-century History|
|It’s a Free-for-All!||It’s a Free-for-all!|
|Uses of Anti-inflammatory Drugs||Uses of Anti-inflammatory Drugs|
|Several Virgil-esque Poets||Several Virgil-esque Poets|
|Mid-Atlantic States||Mid-Atlantic States|
Check if the style guide you’re following provides guidance on this point. If in doubt, default to the modern style. And be consistent; don’t switch between the two styles for different titles.
Other uses of hyphens
There are a few other uses of hyphens left to cover:
- Suspended hyphens
- Hyphens used to indicate stuttering in speech
- Hyphenation of spelled-out numbers and fractions
- Hyphens in foreign terms
A suspended hyphen is a hyphen that appears at the end of a word to indicate that it is followed by the same word or suffix as another word that appears soon after it. This avoids the need to repeat that word or suffix. For example, “left- and right-handed” is short for “left-handed and right-handed.”
Suspended hyphens may also be used in the same way with closed compounds, even though there’s no hyphenation in the full term. For example, “pre- and postwar” is short for “prewar and postwar.”
More rarely, a suspended hyphen appears at the start of a word to indicate the repetition of the first word or of a prefix. Style guides often recommend against this usage, as it can be confusing. It’s usually better to just write out both words in full:
- He found himself overworked and -stimulated.
- He found himself overworked and overstimulated.
To indicate stuttering
When reporting speech—as in a work of fiction or a quote from an interview—hyphens can be used to indicate that the speaker stuttered (repeated a particular part of a word) or that they extended a certain sound.
With numbers and fractions
When you spell out a number instead of using a numeral, hyphenation may be required. Style guides usually recommend hyphenating numbers twenty-one to ninety-nine that consist of two words, but not hyphenating hundreds, thousands, and so on.
Examples are shown below for both cardinal (e.g., “twenty-one”) and ordinal numbers (e.g., “twenty-first”).
|0–20||zero, one, seven, ten, eleven, nineteen, twenty||zeroth, first, seventh, tenth, eleventh, nineteenth, twentieth|
|21–99||twenty-one, forty, fifty-six, seventy-five, ninety-nine||twenty-first, fortieth, fifty-sixth, seventy-fifth, ninety-ninth|
|100+||one hundred (and) twenty-five, seven hundred thousand five hundred (and) forty-eight, nineteen thirty-nine (year)||one hundred (and) twenty-fifth, one million seven hundred thousand five hundred (and) forty-eighth|
There is some disagreement about how to spell out fractions. Traditionally, they are always hyphenated (e.g., “one-third”) unless the second number already contains a hyphen (e.g., “one twenty-fifth”). This approach is still recommended by Chicago and MLA.
A newer approach is to hyphenate fractions only when they are used as adjectives before a noun and leave them open in other contexts. This is recommended by APA and Oxford style guides. Examples of the two approaches are shown in the table below.
|Always hyphenate (Chicago and MLA)||Hyphenate only adjectival fractions (APA and Oxford)|
|The motion passed with a majority of two-thirds.||The motion passed with a majority of two thirds.|
|I’m almost five-eighths of the way through.||I’m almost five eighths of the way through.|
|There’s been a one-half increase in the price of bread.||There’s been a one-half increase in the price of bread.|
|The turkey is three-quarters cooked.||The turkey is three-quarters cooked.|
|You can’t win with a one twenty-fifth share of the vote.||You can’t win with a one twenty-fifth share of the vote.|
With foreign terms
If you use a non-English term in your writing, leave the punctuation as it was in the original language, rather than adding or removing hyphens to match the rules of hyphenation in English.
For example, always hyphenate the French term “savoir-vivre,” but never hyphenate the Latin term “a priori”—in both cases, following the style of the original language. If you’re unsure, check a dictionary.
- The policy is somewhat laissez faire.
- The policy is somewhat laissez-faire.
- This was an ex-post-facto decision.
- This was an ex post facto decision.
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Frequently asked questions
- What is a hyphen?
A hyphen (-) is a punctuation mark used to connect two or more words that work together to express a combined meaning or modify a following word. A series of two or more words joined by hyphens is called a hyphenated compound. Examples include “decision-making,” “well-being,” and “high-quality.”
A hyphen is different from an en dash (–), which is used to indicate numerical ranges (e.g., “10–15”) and to mean “to” in other contexts (e.g., “the Brussels–London train”).
It’s also not the same as an em dash (—), which is used to indicate a break in a sentence or set off a parenthetical statement (e.g., “What I’m saying—and stop me if you’ve heard this before—is that …”).
- When do you use a hyphen?
A hyphen (-) is used to connect two words and show that they should be read in combination to express one meaning. The main contexts where hyphenation is needed are:
- Do you hyphenate numbers?
When you spell out numbers from twenty-one to ninety-nine that consist of more than one word, hyphenate them. For example, write “thirty-six,” not “thirty six.”
But don’t hyphenate terms for larger numbers such as “hundred,” “thousand,” and “million.” For example, write “three thousand four hundred (and) twenty-seven” and “nineteen sixty-eight.” (Such numbers are normally written as numerals anyway: “3,427”; “1968.”)
- Is there a hyphen in “in person”?
The phrase “in person” should be written with a hyphen in some contexts but not others.
Don’t hyphenate it when it does not appear before a noun: “I’ve met her in person,” “we work together in person,” “we have never spoken in person.”
- Is there a hyphen in “year old”?
Phrases describing age, such as “one-year-old,” are hyphenated in some contexts but not others.
Hyphenate when the phrase functions as an adjective before a noun (e.g., “two-year-old daughter,” “six-week-old puppy”) or when it functions as a noun (e.g., “he behaves like a four-year-old,” “the 10-year-old was staring”).
Don’t hyphenate when the phrase is used as an adjective after the noun. In this case, the unit of time is also pluralized (e.g., “years”) unless the number is one. For example, “my daughter is two years old,” “he behaves like he’s four years old,” “the puppy is one month old.”
- How do I hyphenate last names?
Some people have “double-barreled” last names such as “Smith-Merkus,” for example because both parents retained their original surnames when they married.
There is no consistent rule about whether such last names should be hyphenated. Hyphenation varies widely according to cultural context and personal choice.
To know whether a specific person’s last name is hyphenated, it’s best to check a reliable source such as the title page of one of their publications or an entry about them in a reference work.
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