Using Brackets in Sentences
It’s important to note before we get started that, as with any type of punctuation, there are always exceptions to rules and, of course, other rules that may not be discussed here. When in doubt, look it up or ask your teacher for clarification. This last point is particularly important because, depending on the field of study and style guide being used, bracket rules can change.
Now, there is often confusion between parentheses and brackets because they look so similar. However, they are not the same thing, so make sure to avoid using brackets and parentheses interchangeably. Parentheses are more common, and the two should rarely be substituted for each other (we’ll look at an exception to this rule later).
Parentheses = ( )
Brackets = [ ]
Parentheses are sometimes referred to as round brackets, while brackets are sometimes referred to as square brackets. If you just encounter the word “brackets,” it’s safe to assume that this is shorthand for “square brackets” as opposed to parentheses.
Now let’s look at the rule for using brackets.
Rule Number 1: Clarification
This rule applies to quoted material. If a quotation is missing pertinent information or is quoted without context, an editor or writer can add brackets to clarify what the original text was referring to.
In his memoirs, the author reveals, “The year we moved into the house  was a difficult time for us, both emotionally and financially.”
Note here that the quotations are missing crucial information that could lead to confused readers: the year 1985 in the first example and the “they” being referred to in the second. The bracketed portions clarify this information for the reader. Note that the bracketed material is an addition and not a substitution.
Rule Number 2: Translation
This rule serves as an extension of the first. In this case, use brackets to translate a phrase or word that readers may be unfamiliar with in a quotation. If the phrase or word being translated is not in a quotation, then use parentheses. Here’s an example:
“I seldom spoke French in class. When I did, I usually just said je ne sais pas [I don’t know.]”
Because the phrase je ne sais pas is foreign and inside a quote, the translation of the phrase has been placed in brackets.
Rule 3: Showing a Change in Capitalization
Quotations should make sense in terms of capitalization when they are integrated into your writing. Use brackets around the first letter in a quotation in order to show that the letter was in a different case in the original quotation. For example:
Under the terms of his employment contract, his “[p]erformance-based stock options shall not vest until December 31, 2025.”
In this quote, the word performance was originally capitalized. Since the quote is the continuation of a sentence outside of the quote, we placed the lowercase P in brackets.
Rule Number 4: Showing Errors in a Quotation
When using a quotation with a grammatical or spelling error, then include [sic] after the error. This tells readers that the mistake is not your own, but it’s from the original source. For example:
The final report indicated that “pilot error ways [sic] the most likely cause of the crash.”
In this example, “ways” should be “was.”
If you want to avoid brackets in this particular situation, consider simply paraphrasing in order to avoid using [sic].
Rule Number 5: Emphasis
Sometimes you might want to italicize material in a quotation in order to emphasize that portion of the text. When doing so, be sure to include [emphasis added] to show readers that these italics were not in the original quotation. For example:
“She told her students they could miss class only once [emphasis added].”
Rule 6: Parenthetical within a Parenthetical
When there are parentheses within a phrase already surrounded by parentheses, then use brackets to replace those parentheses. For example:
Cormac McCarthy published several novels (including The Road (2006)).
Since the parentheses around 2006 are inside another set of parentheses, we need to change them to brackets.
Cormac McCarthy published several novels (including The Road ).
Note that this particular rule may not apply if you are using certain style guides, so be sure to double-check before using brackets in this way.
Ok, now that we’ve gone over the rules, let’s test your knowledge with a review question:
When should brackets not be used?
- When indicating clarification in a quotation
- When indicating emphasis
- When a parenthetical appears within a parenthetical
- Interchangeably with parentheses
The correct answer is D. Be careful to use brackets and parentheses correctly and not accidentally swap them.
I hope this review was helpful! Thanks for watching, and happy studying!