Hyphens, ‘en’ dashes, and ’em’ dashes are three distinct punctuation marks that all tie to the same key on most keyboards. This makes it easy to misuse the useful marks, so it’s helpful to know how each one is used.
Hyphens (-) are the shortest of the dashes. Use them:
Between words in compound adjectives-words that work together to describe one noun.
Example: It’s a dog-eat-dog world.
Between numbers that are not inclusive, such as phone or document numbers.
Between prefixes and proper nouns.
Example: Pre-Galilean scientists thought the world was flat.
To separate prefixes from words that might look awkward.
Example: co-opt; pre-evaluation
To type a hyphen: Hit the ‘minus’ key, which is typically to the right of the ‘0′ key.
‘En’ dashes (-) are longer than hyphens but not as long as ‘em’ dashes. Use them:
Between numbers that are inclusive, such as ranges.
Example: She worked at the company from 2000-2002.
Between words when a transition is implied, just like you would use ‘to.’
Example: The pilot flew the New York-London route.
To combine an already-hyphenated compound adjective into a bigger compound expression.
Example: High-risk-high-reward investments . . .
To type an ‘en’ dash:
With ‘Num Lock’ on, press ‘Ctrl’ and hit the ‘minus’ key on the numeric keypad.
Alternately, press ‘Alt’ and enter 0150 on the keypad.
‘Em’ dashes (-) are the longest dashes. An ‘em’ is a unit of measurement in typography, so an ‘em’ dash is one ‘m’ long. Use ‘em’ dashes:
Between a noun or series of nouns and its pronoun.
Example: Passion, integrity, and ingenuity-these qualities are . . .
Between a noun and a phrase that explains the noun
Example: Without the necessary tools-nails, a hammer, and duct tape- the students couldn’t decorate their dorms.
To insert a related thought into a sentence
Example: Even though I’ve been late twice this week-this time it wasn’t my fault- I can assure you it won’t happen again.
To type an ‘em’ dash:
Hit the ‘minus’ key twice, type the next word, and then hit the space bar, or
With the number lock on, press Ctrl, Alt, and 0151 on the numeric keypad.
Here is what one of our Timely Tip recipients had to say:
“I am not a grammar wizard by any stretch of the imagination. I started out average, then went to engineering school to get any grammar and communication skills beaten out of me.”
– P. Wallace, ConocoPhillips