Hyphen Rules in English with Examples

A hyphen (-) is a short punctuation mark that joins words or parts of words. It helps readers see that separate words are connected and should be understood as one unit.

Compare:

• a man-eating shark — a shark that eats people
• a man eating shark — a man who is eating shark meat

The small mark changes the relationship between the words. However, not every compound needs one. Some compounds are written as one word, some remain open, and others are hyphenated.

Hyphens in Compound Words

A compound word combines two or more words to express one idea. Compound words have three common forms:

There is no single rule that predicts the form of every compound. The accepted spelling often develops through common usage.

For example:

• email was once commonly written as e-mail
• online was previously seen as on-line
• website was once frequently written as web site

Use a current dictionary when you are uncertain about an established compound.

Some compounds change form according to their grammatical function:

The hyphenated or closed form is often a noun, while the open form is usually a verb.

Compound Adjectives before Nouns

A compound adjective contains two or more words that work together to describe a noun. When it appears before the noun, it is usually hyphenated.

• a ten-minute conversation
• a full-time position
• a well-written report
• a high-speed train
• a last-minute decision
• an easy-to-follow guide
• a four-bedroom house
• a world-famous athlete

The hyphen shows that the words belong together:

• a small-business owner
  The person owns a small business.

Without the hyphen, the reader may initially think that small describes the owner.

Before the noun and after the noun

Many compound adjectives lose their hyphens when they come after the noun.

Some established compound adjectives remain hyphenated after the noun. Check a dictionary when the expression has a recognised spelling.

Do not hyphenate an adverb ending in -ly

An adverb ending in -ly clearly modifies the adjective that follows it, so a hyphen is unnecessary.

Correct:

• a highly skilled worker
• a carefully planned event
• a recently published article
• a beautifully decorated room
• a widely recognised problem

Incorrect:

• a highly-skilled worker
• a carefully-planned event
• a recently-published article

An adverb that does not end in -ly may need a hyphen:

• a well-prepared student
• a fast-moving vehicle
• a much-needed break
• a best-selling novel

Do not hyphenate proper-name modifiers unnecessarily

A proper name already forms a recognisable unit.

• a New York restaurant
• a Shakespeare play
• a United Nations meeting

A hyphen may still appear when the proper name becomes part of a longer compound:

• a New York-based company
• a Shakespeare-inspired drama
• a United Nations-supported programme

Hyphens with Prefixes

A prefix is added to the beginning of a word, such as un-, re-, pre-, non-, or anti-.

Most prefixes join directly to the base word:

• unhappy
• rewrite
• prepaid
• inactive
• misunderstand
• international
• semicircle
• overcrowded

Use a hyphen in the following situations.

With self-, ex-, and all-

These prefixes commonly take hyphens:

• self-control
• self-employed
• self-confidence
• ex-manager
• ex-wife
• ex-president
• all-inclusive
• all-knowing
• all-purpose

Do not confuse ex-, meaning “former,” with words that naturally begin with ex:

• ex-teacher — a former teacher
• extend — not a prefixed form
• explain — not a prefixed form

Before a capital letter or proper noun

Use a hyphen when a prefix is attached to a proper noun, capitalised word, or abbreviation.

• anti-American
• non-European
• pre-Roman
• post-Victorian
• pro-democracy
• non-English-speaking
• mid-July
• non-EU countries

To prevent confusion

A hyphen can separate forms that would otherwise look confusing or create another word.

Modern dictionaries sometimes accept closed forms such as reenter or cooperate. British and American spelling preferences may also differ, so consistency matters.

When the prefix ends and the base begins with the same vowel

A hyphen may improve readability:

• anti-inflammatory
• semi-independent
• pre-existing
• re-elect
• co-operate

Some of these words also have accepted closed spellings, such as preexisting or cooperate. Follow the spelling used by your dictionary or publication.

Hyphens in Numbers and Ages

Compound numbers from twenty-one to ninety-nine

Hyphenate written compound numbers between twenty-one and ninety-nine.

• twenty-one
• thirty-six
• forty-five
• seventy-eight
• ninety-nine

The rule also applies when the number forms part of a larger number:

• one hundred and twenty-five
• three hundred and sixty-two
• one thousand nine hundred and forty-seven

Only the compound number below one hundred is hyphenated.

Fractions written in words

Written fractions are commonly hyphenated when they function as nouns or modifiers.

• two-thirds of the class
• a one-half share
• a three-quarter majority
• four-fifths of the building
• a two-thirds reduction

Do not add a hyphen when the fraction is introduced by a and used as a simple noun phrase:

• half an hour
• a quarter of the cake

Ages used before nouns

Hyphenate an age when it describes a noun.

• a five-year-old child
• a twelve-year-old student
• a two-month-old puppy
• an eighty-year-old building

Notice that year and month remain singular inside the compound adjective.

Incorrect:

• a five-years-old child
• a two-months-old puppy

Correct:

• a five-year-old child
• a two-month-old puppy

Ages used as nouns

A hyphenated age expression can also identify a person or animal.

• The competition is open to six-year-olds.
• A twenty-year-old answered the door.
• The class includes several fourteen-year-olds.

The plural ending is added to old, not to year.

Ages after nouns

Do not use hyphens when the age comes after the noun.

Hyphenated Nouns

Some compound nouns have established hyphenated spellings.

Common examples include:

• mother-in-law
• father-in-law
• sister-in-law
• brother-in-law
• passer-by
• runner-up
• editor-in-chief
• merry-go-round
• self-esteem
• check-in
• dry-cleaning
• X-ray

Forming plurals

In many multiword compounds, the main noun becomes plural.

Other hyphenated nouns take the plural ending at the end:

• check-ins
• X-rays
• drive-throughs
• grown-ups

Use a dictionary if the main word is not obvious.

Noun and verb differences

Some expressions are hyphenated as nouns but written separately as verbs.

• We had a short get-together.
• Let us get together on Friday.
• The system requires a log-in.
• You must log in first.
• The police began a follow-up.
• They will follow up on the report.

Usage varies for newer terms. For example, many dictionaries now prefer login as one word when it is a noun or adjective.

Hyphen vs Dash

A hyphen and a dash are different punctuation marks. They perform different jobs and have different lengths.

Hyphen

A hyphen joins connected words:

• sugar-free drink
• twenty-seven
• ex-president
• six-year-old

It is written without spaces.

En dash

An en dash commonly shows a range:

• 2018–2026
• pages 15–30
• Monday–Friday
• the Lahore–Karachi route

It usually means to or through.

Do not combine from with an en dash:

Incorrect:

• from 9:00–11:00

Correct:

• from 9:00 to 11:00
• 9:00–11:00

Em dash

An em dash marks an interruption, an added thought, or a strong break in a sentence.

• The answer—although nobody admitted it—was obvious.
• She opened the envelope—and screamed.
• Three people knew the truth—Ali, Sara, and Hamza.

An em dash does not join compound words.

Common Errors

1. Do not hyphenate every pair of adjectives.
   Incorrect: a beautiful-old-house
   Correct: a beautiful old houseThe adjectives describe the noun separately.
2. Hyphenate words that act as one modifier before a noun.
   Incorrect: a ten minute break
   Correct: a ten-minute break
3. Do not use a hyphen after an adverb ending in -ly.
   Incorrect: a poorly-written answer
   Correct: a poorly written answer
4. Keep measurement words singular inside compound adjectives.
   Incorrect: a five-kilometres-long road
   Correct: a five-kilometre-long road
5. Do not hyphenate an age after the noun.
   Incorrect: My son is six-years-old.
   Correct: My son is six years old.
6. Do not use an apostrophe in age compounds.
   Incorrect: a seven-year-old’s boy
   Correct: a seven-year-old boy
7. Do not replace a dash with a hyphen.
   Incorrect: The office is open Monday-Friday.
   Better: The office is open Monday–Friday.
8. Do not separate a hyphen with spaces.
   Incorrect: a part – time worker
   Correct: a part-time worker
9. Do not hyphenate a phrasal verb.
   Incorrect: Please log-in now.
   Correct: Please log in now.
10. Check the dictionary form of established compounds.
    Incorrect: note-book
    Correct: notebookIncorrect: postoffice
    Correct: post office

Practice Exercise

Add hyphens where they are needed. Remove any unnecessary hyphens.

1. We attended a two hour meeting.
2. She is a highly trained engineer.
3. My ten year old nephew loves science.
4. The company hired twenty five workers.
5. He decided to re sign the contract for another year.
6. They live in a three storey house.
7. The house is three storeys old.
8. This is a well researched article.
9. Sara works full time at the hospital.
10. We need a full time assistant.
11. Her mother in law lives nearby.
12. The shop is open Monday-Friday.

Answers

1. We attended a two-hour meeting.
2. She is a highly trained engineer.
3. My ten-year-old nephew loves science.
4. The company hired twenty-five workers.
5. He decided to re-sign the contract for another year.
6. They live in a three-storey house.
7. The house is three storeys old.
8. This is a well-researched article.
9. Sara works full time at the hospital.
10. We need a full-time assistant.
11. Her mother-in-law lives nearby.
12. The shop is open Monday–Friday.

Short Summary

1. A hyphen joins words that function together as one unit.
2. Compound adjectives are usually hyphenated before nouns.
3. Adverbs ending in -ly normally do not take a hyphen.
4. Most prefixes attach directly, but forms such as self-, ex-, and all- usually require one.
5. Written numbers from twenty-one to ninety-nine are hyphenated.
6. Use hyphens in ages before nouns: a six-year-old child.
7. Do not hyphenate ages after nouns: The child is six years old.
8. A hyphen joins words, while dashes show ranges or breaks in sentences.

Hyphen Rules and Examples PDF

Frequently Asked Questions