Dashes and parentheses indicate an “aside” to the point you are making in your sentence. Although sometimes considered interchangeable, each serves a specific purpose in your writing. Dashes interrupt your writing to insert an interjection or pause, while parentheses gently add information to your point. A word of caution: although parentheses can be used throughout all writing genres, dashes are rarely used in formal academic research. Dashes are more common in fiction writing and in more casual texts. Another word of caution: make sure that you are introducing relevant additional information with your dashes or parentheses and that it is not just added for fluff. Strive to be clean and clear in your writing.

In this handout, we have provided some guidelines for using each punctuation mark.

The Dash

An em dash—inserted by typing Control+Alt+Minus between the words it separates—signals an abrupt break in thought. It can be seen as “surprising” the reader with information. If used judiciously it can mark a longer, more dramatic pause and provide more emphasis than a comma can. If overused, it creates an impression of haste and carelessness and can diminish cohesion in your paragraphs. Em dashes are useful in early drafts to capture thoughts and afterthoughts, but in revising you may need to delete them in favor of punctuation marks that better express your ideas, such as commas (see our handout on Commas for more information). Think carefully before peppering your papers with them.

Tip: When using the em dash in a sentence, you do not place spaces on either side of the punctuation mark, except in some journalistic styles of writing.

If you wish to use dashes effectively here are some guidelines:

If the main sentence resumes, a second dash is needed. Don’t allow a comma to substitute for the second dash, and be sure that your sentence would make sense if the part without the dashes were omitted:

Example: The actors bowed—except for the horse—knowing they blew everyone away!

If the main sentence resumes, a second dash is needed. Don’t allow a comma to substitute for the second dash, and be sure that your sentence would make sense if the part without the dashes were omitted:

Example: The actors bowed—except for the horse—knowing they blew everyone away!

Don’t combine dashes with other punctuation marks:

Inappropriate: They acquired several horses at the fair, —a winner, a loser, and a beer-drinking mare.

Appropriate: They acquired several horses at the fair—a winner, a loser, and a beer drinking mare.

Use dashes to mark the beginning and end of a series, which might otherwise get confused, with the rest of the sentence:

Example: The three female characters—the wife, the nun, and the jockey—are the incarnation of excellence.

Dashes are also used to mark the interruption of a sentence in dialogue:

Example: “Help! This horse is going too fast,” the actor yelled. “I think I am fall—.”

NOTE: Colons are preferred when introducing a list. See our Colons handout for more information.

The Parentheses

Parentheses also signify a break in thought, but they mark an addition of information rather than an interruption like dashes do. Rather than a surprise (like dashes), parentheses are a gentler insertion in your sentence. Also like dashes, parentheses should be used sparingly. Too many can break the clarity and flow of your ideas. Another thing to keep in mind is that they are often seen as casual in tone, so make sure they are appropriate for the style of writing you are using. If not, punctuation marks such as commas are often more academically appropriate.

If you wish to use parentheses effectively here are some guidelines:

Parentheses can be used to set off incidental information such as numbers, dates, examples, and references:

Example: The show will run for a staggering seventeen (17) weekends.

Example: A recent study examined wellness practices among Kentucky Derby winning jockeys (Calamine, 2012).

Example: The use of “human” as a noun (“Humans are sentient beings”) has been criticized.

No mark of punctuation should ever precede a parentheses, but you can use punctuation after the closing parentheses if necessary. The rule is that the parentheses shouldn’t affect the punctuation of the main statement:

Example: After several weeks of exercises (memory and voice), he finally began to feel competent.

If the enclosed matter is the last part of the sentence, the period comes after the parentheses, as in the next example:

Example: Horses should be regarded as assets (but only the working kind).

Like dashes, parentheses can be overused, as in:

Example: Though making a production about a winning horse has its dilemmas (having the space and the janitors necessary) and the normal problems expected in any play (big egos, emotional cast, and a low budget), it is an immense satisfaction to make it happen.

NOTE:  Dashes and parentheses are great tools to use when you need to add additional information in your sentences. However, keep in mind that they must be used judiciously, and sparingly. If used too often they can complicate the flow of your sentences, which can confuse your reader. Almost any instance of a dash or parentheses is going to be “fluff” or unnecessary, so it is up to you to decide whether the information you want to add is worth the risk of cluttering up your sentences.