Dash vs Hyphens - Which to use and When?
A dash is a character that is longer than a hyphen and is commonly used to indicate a range or pause. The en dash (–) and the em dash (—) are the two most common types of dashes.
A hyphen (-) is a punctuation mark that joins words or parts of words together. It cannot be used in place of other types of dashes.
Hyphens Usage
Some compound words are hyphenated, such as self-control. When spelled out, numbers between twenty-one and ninety-nine should also be hyphenated. However, if you're not sure whether a compound word needs a hyphen, consult a dictionary or style guide. Over time, hyphenated words become closed compounds (single words without hyphens). For example, using email instead of e-mail is becoming more common.
A hyphen should also be used before a noun when a compound modifier is used. A compound modifier (also known as a phrasal adjective) consists of two or more words that must be understood together. Because big and bright do not form a unit of meaning, “a big, bright hotel” does not contain a compound modifier. However, “a dog-friendly hotel” does contain a compound modifier; the phrase makes no sense unless you understand “dog-friendly” as a unit of meaning. The hyphen informs the reader that the words should be considered together as a noun descriptor. Compound modifiers are typically made up of an adjective and a noun or participle. They're also frequently made up of a noun and a gerund.
closed-door meetings in a dog-friendly hotel a flower-filled vase for a book-loving student (this means that the vase is expensive) a vase brimming with pricey flowers (this means that the vase is filled with expensive flowers)
But keep in mind that when a compound modifier comes before a noun, it only requires a hyphen. Leave the hyphen out if it comes after the noun.
The hotel welcomes dogs.
Another caveat: if you have a compound modifier that consists of an adverb ending in -ly plus a participle or adjective, don't use a hyphen. The suffix -ly suffices to establish that the compound is a linguistic unit.
a well-regarded scientist a deliciously cooked steak an extremely embarrassing Facebook post
Use a suspended hyphen when a compound modifier is interrupted by another word that isn't really part of the modifier:
Take a five- or ten-minute break from your work.
Hyphens are also frequently used to separate words that end one line of text but continue on the next. Although this method of setting type is still used by book and newspaper publishers, it is no longer necessary to manually insert word breaks in your own writing because modern word processors automatically justify and align your text. If you must split a word at the end of a line, it is best to do so between syllables.
When Should You Use En Dashes?
En dashes are frequently mistaken for hyphens because they are about the width of an upper-case N. En dashes, on the other hand, are commonly used as a type of super hyphen. When you have a compound modifier with a multi-word element that can't be easily hyphenated, they're meant to give you a little extra glue. For example, an en dash is used in the phrase Elvis Presley–style dance moves because Elvis Presley–style dance moves is awkward; “Elvis Presley” isn't a compound modifier, so hyphenating it looks strange. However, keep in mind that not all readers will notice or understand en dashes. It's sometimes easier to simply rephrase the phrase.
Pre–World War II buildings or: buildings constructed before World War II dance moves or: dance moves like Elvis Presley's pre–World War II buildings or: buildings constructed before World War II
En dashes are also used to indicate numerical ranges, such as times, page numbers, or scores (I'll schedule you between 4:30 and 5:00). This type of en dash is commonly replaced with a simple hyphen outside of formal printed publications.
When Should You Use Em Dashes?
Compared to the more technical hyphen and en dash, the em dash (roughly the width of an uppercase M) is a more artistic punctuation mark. In most cases, an em dash is used to indicate a pause in a sentence. It's more powerful than a comma, but not as powerful as a period or semicolon.
To draw special attention to parenthetical information, use a pair of em dashes:
With a tray of Jello, the new nurse entered the room, wearing the same purple scrubs as the old nurse.
When the information is surprising, a single em dash can be used as a colon to add explanatory or amplifying information:
When I opened the door, she was standing there—my long-lost sister.
Em dashes can also indicate a sudden break in the action, especially in dialogue:
“Wait! I almost forgot to mention—” The door between us slammed shut, and I didn't hear what she was trying to say.
It's a personal preference whether you use spaces around your em dashes (word—word or word—word). Use the same style throughout your document, whichever one you choose.
Remember that em dashes and hyphens are not interchangeable. Readers will be confused if you use a single hyphen instead of an em dash, and your writing will appear unprofessional. If you're writing text in a programme or on a website where the em dash character isn't available, make an em dash by combining two hyphens (–).
