Brackets usage in English: General guidelines and rules

Brackets are one of the most confusing punctuation marks in English grammar. Generally, they are used to add extra details to a sentence (an explanation, additional comments, or clarification, like in this sentence). If you remove the bracketed content, a sentence should make sense and its meaning should not be distorted. Also, note that brackets are always used in pairs.

Students are often confused because there are several types of brackets:

- round brackets, or parentheses: ( )

- square brackets: [ ]

- curly brackets: { }, and

- angle brackets: < >;.

Each type of bracket has its rule of usage. In this article, we are going to focus on parentheses and square brackets since they are used most commonly.

Using parentheses in English

Round brackets, also called parentheses in American English, are the most common type of braces. Their main function is to introduce additional information or clarification in a sentence. These additional details can also be set off with commas.

Here are the most popular scenarios when you can use round brackets:

-To explain or provide additional detail: Margaret Thatcher (Europe’s first prime minister) was elected for three consecutive terms. - To include a personal note or clarification: Some people believe that waking up at 5 AM gives you a productivity boost (it didn’t work for me, though). - To decode an abbreviation:

WTO (The World Trade Organization) plays a key role in food crisis prevention.

Check yourself: if you are using parentheses right, you can remove the bracketed content completely and the main idea of the sentence will still remain unchanged.

Also, note that the full stop or question mark is placed after the closing bracket. This rule applies to all types of brackets.

Square brackets: when and how to use

Square brackets, or brackets in American English, are typically used to insert comments from the other person, not the original writer. Generally, this is done to clarify the meaning or to point out a mistake.

Here’s how to use the brackets correctly:

- To clarify the author’s words or add information: James Lee [the grocery store owner] stated that they hired a new employee two days ago.

- To add an editorial comment or show an error in the original text: The handwritten note said: “Call me when you come back from Phenix [Phoenix]”.

The speaker pointed out that global temperature growth by 2 degrees will significantly increase the accumulated heat [my emphasis].

- To include more information within parentheses: Rachel hosted a party and had to take care of everything (including food, drinks [soft and alcoholic], and music).

The usage of angled and curly brackets

Both of these bracket types have very limited use in modern English. Braces, for example, are used in computer programming, math formulas and chemical equations. Humanities students may not encounter them whatsoever.

Angle brackets are used in academic writing to insert a URL of the source in the text. Another example of usage is indicating foreign speech in comic books. However, these two types are used very rarely compared to parentheses and brackets.