How to Use Hyphens, En Dashes and Em Dashes

English has three horizontal lines that look alike but do different jobs. The hyphen (-) is the shortest and joins words. The en dash (–) is a little longer and shows ranges. The em dash (—) is the longest and works like a strong comma or a pair of brackets. Picking the right one is a small detail, but it makes writing look more polished.

The hyphen: joining words

Compound adjectives

When two or more words work together as a single adjective before a noun, join them with hyphens:

• a high-scoring word
• a two-letter word
• a last-minute change
• an up-to-date dictionary

The hyphen prevents confusion. A small business owner could be a small person who owns a business; a small-business owner owns a small business.

When the same words come after the noun, the hyphen usually disappears:

• This dictionary is up to date.
• The word is high scoring.

Do not hyphenate -ly adverbs

Adverbs ending in -ly already make it clear what they modify, so no hyphen is needed:

• ✗ a highly-rated game
• ✓ a highly rated game

Numbers and fractions

Use hyphens in compound numbers from twenty-one to ninety-nine and in fractions used as adjectives:

• twenty-one, forty-two, ninety-nine
• a two-thirds majority

Prefixes

Most prefixes join without a hyphen (rewrite, preheat, nonstop). Use a hyphen when:

• the base word is capitalised or a number: pre-1990, un-American, mid-July
• the prefix is self-, ex- (meaning former) or all-: self-aware, ex-champion, all-inclusive
• leaving it out would create confusion: re-cover (cover again) versus recover (get better); re-sign (sign again) versus resign (quit)

Compound nouns

Some compound nouns are hyphenated (mother-in-law, runner-up), some are closed (notebook, crossword) and some are open (word game, high school). There is no rule that covers them all, and style changes over time: e-mail has largely become email. When in doubt, check a current dictionary.

The en dash: ranges and connections

The en dash, roughly the width of a capital N, means "to" or "through":

• pages 45–60
• the 2024–2025 season
• Monday–Friday
• a 3–2 victory

It also connects two equal terms in a relationship:

• the London–Paris train
• a teacher–student conference

Do not combine the en dash with from or between. Write from 2010 to 2020 or 2010–2020, but not from 2010–2020.

The em dash: breaks and emphasis

The em dash, roughly the width of a capital M, is the most flexible of the three. It can replace commas, brackets or a colon, and it adds emphasis.

To set off extra information (like a pair of commas, but stronger):

• The champion — who had never lost a tournament — made a rare mistake.

To mark a sudden break or change in thought:

• I was sure the word was valid — until I checked.

To introduce an explanation or a list (like a colon, but more informal):

• She needed one thing to win — an S.

Use em dashes sparingly. One or two in a paragraph adds punch; more than that makes writing feel breathless.

Spacing

American style usually sets the em dash without spaces (word—word). Many British and online publications use an en dash with spaces instead (word – word). Both are acceptable; pick one style and use it consistently.

Hyphen, en dash or em dash? A quick guide

How to type them

Most word processors also turn two hyphens into a dash automatically as you type.

Hyphens in word games

Hyphenated words are not allowed in Scrabble, Words With Friends or most daily word puzzles. That is why MOTHER-IN-LAW never appears on a board, but some compounds that are written as one word, such as CROSSWORD, NOTEBOOK and RUNAROUND, are perfectly playable. If you are unsure whether a compound is closed, check it in the word checker.

Practice quiz