Parentheses are a popular way to add information to a sentence without breaking its flow, but they come with some very specific rules. These punctuation marks are an excellent way to give your reader some insight into your main idea and are used to interject details and asides in a simple, informal manner.
However, they are easy to overuse or use incorrectly. Take a look at our parentheses rules of use, capitalization, and punctuation examples to apply to your own writing.
What Are Parentheses?
Parentheses (singular: parenthesis), also known as round brackets outside the United States, set off supplementary materials that are not essential to understanding the sentence. Parentheses are the strongest separator for asides, explanations, and numerical details.
Rules of Parentheses Use With Examples
There are two key concepts to consider to help you determine when the use of parentheses is appropriate. Use the following rules to help define whether you should use them within your sentence to help provide detailed information to the reader for clarity and understanding.
It is important to avoid overusing parentheses, leading to choppy, unclear prose and confusion for the reader.
Parentheses Rule #1
Use parentheses to set off explanations and asides only when the information is not essential or when it comprises one or more sentences. You should be able to remove all the material within parenthesis without changing the sentence’s meaning.
- Jonathan perfected his free throw shot (after months of practice at home) and will now start as his team’s first string.
- We ordered the new uniforms last week. (The saleslady promised they would be ready today.) Unfortunately, we are still waiting for them to arrive.
Parentheses Rule #2
Use parentheses to set off numerical explanations such as numbers and letters that represent a series or to detail dates of specific events.
- Michael Smith (1922 – 2008) created his family business from the ground up to make it the successful storefront it is today.
- You’ll need to raise at least five hundred dollars ($500) to attend that summer camp.
- Pick up the following from the home goods store: (1) shampoo, (2) dryer sheets, (3) new bathroom towels.
Capitalizing and Punctuating With Parentheses
Using parentheses raises questions about capitalization and punctuation, and these rules can be tricky if you don’t remember the following guidelines that can help your writing stay grammatically correct. Keep in mind these four key concepts to help you determine how to apply basic grammar rules for fluency.
Capitalization and Punctuation Rule #1
If a phrase or declarative sentence interrupts another sentence, do not use an initial capital or end mark within the parentheses.
- We studied long hours (sometimes until midnight) when preparing for the exam.
Capitalization and Punctuation Rule #2
If an exclamation or question interrupts another sentence, use both an initial capital and an end mark within the parentheses.
- The National Hockey League matches (These have some of the most famous players in the world!) reach millions of viewers throughout their regular season.
Capitalization and Punctuation Rule #3
If a complete sentence falls between two complete sentences, use both an initial capital and an end mark within the parentheses.
- We traveled ten hours that first day. (It was exhausting.) The closer we got to Florida, the more excited we became.
Capitalization and Punctuation Rule #4
Sentences that include a parenthesis place punctuation that belongs to the main sentence after the closing parenthesis.
- His free-throw average set several records (5 this season), and he helped his team take the State title.
Examples of Parenthesis Use
Consider these additional examples use of parentheses to help make these rules clear:
If the text within the parentheses is syntactically integrated with the surrounding sentence, keep the end punctuation outside the parentheses—for example:
- Punctuating parentheses is easy (if you know where to put the period).
But parenthetical information does not always have to be syntactically integrated. For example, a ‘with’ is implied but omitted at the start of this parenthetical text:
… Trump grew up in a big house (some two dozen rooms, twenty-foot Georgian columns on the portico) in the same borough of New York. [New Yorker]
If the material within parentheses is a complete sentence and does not fall in the middle of a non-parenthetical sentence, consider making the sentences separate. Include the parenthetical text’s end punctuation within the closing parenthesis—for example:
- Most of the guests had hamburgers. (The only exception was Ralph.) They were made to each guest’s specific order.
But, sometimes a complete sentence within parentheses may be enclosed within another sentence. In this case, no end punctuation is needed for the parenthetical text—for example:
- Most of the guests (the only exception was Ralph) had hamburgers.
When parenthetical text takes a question mark or exclamation point, put this punctuation within the parentheses—for example:
- We saw a small, red bird (a cardinal?) in the tree.
- The low price ($10!) made the hamburger combo irresistible.
The use of parentheses helps add details and clarification, but the information found within its punctuation isn’t necessary for a reader to understand the sentence. Be sure to follow the specific rules that apply to asides, letters, or numbers, and pay particular attention to capitalization and punctuation to avoid grammatical errors.