Parentheses and brackets are handy little tools used to separate text within text. Used judiciously, they can make the text smooth and clear. Overused, as Roy Peter Clark warns, these punctuation marks can make your writing choppy and hard to read. Below are some tips for using both parentheses and brackets.
Follow these conventional uses of parentheses:
Use parentheses to set off dates or other clarifying material within a sentence.
Please inform me if the meeting date (Tuesday, October 9) is acceptable.
Use parentheses to indicate an aside or afterthought.
Please review the updates to the new training module. (Aisha will create a username and password for you.)
Use parentheses to set off numbers in a list within a sentence.
Before we can implement the program, we need to explore (1) the necessary time frame, (2) cost factors, and (3) impact on personnel.
Use parentheses to set off references to authors, titles, or pages within a sentence.
The research clearly shows that this program will help increase employee efficiency (Smith 12).
Use parentheses to supply a technical term or translation.
The Eastern Red Cedar (Juniperus virginiana) is Briar Hill Nursery’s best seller.
Follow these conventional uses of brackets:
Use brackets if you are quoting someone and need to add material to make the quotation understandable.
Jan said, "Once the committee saw them [the results], the decision to continue funding our research was unanimous."
Use brackets around the Latin word sic, which is used within a quoted passage to show that the error was made by the original speaker or writer.
The end of the report read, “We hope you agree with our purposed [sic] recommendations."
Use brackets for unavoidable parentheses within parentheses.
Jillian (and EMT workers) was at the scene. (This sentence requires a singular verb [was] because words in parentheses cannot be a part of the subject.)
- Rewrite portions of text that include too many parentheses.
- Do not use parentheses and brackets interchangeably.
- Do not treat information within parentheses or brackets as part of the sentence’s subject. (See an example under the final usage for brackets.)
- If parentheses come at the end of the sentence, place end punctuation outside the parentheses.
We edited the new social marketing video to fall within the optimal duration for sustained engagement (around or under 90 seconds).
- If parenthetical material is its own sentence, capitalize it and punctuate it separately.
Please watch the video. (It is 64 seconds.)
- Do not separately capitalize and punctuate a sentence within a sentence.
The video on YouTube (it has 12,000 views) is our most popular.
Expanding Your Craft
Did you know a set of parentheses is one of three ways to set off a sentence interrupter—an explanatory word or phrase that interrupts the main action of a sentence? The other two are commas and dashes. The type of punctuation surrounding the interrupter can affect the way it is read:
- Commas signal extra information added to the main part of the sentence.
- Dashes emphasize the interrupting information.
- Parentheses de-emphasize the interrupting information.