Parentheses, also known as brackets in the UK, are a useful tool in writing. They help you set off parts of a sentence that add extra information or are less important than the main content. This article covers what parentheses are, when to use them, and even how to handle parentheses within parentheses.
Parentheses ( )
What Are Parentheses?
Parentheses () are punctuation marks that always come in pairs: you are very unlikely to see a sentence with just one parenthesis in it. Parentheses are used to give details about the topic and to indicate a phrase that interrupts the natural flow of a sentence.
Learn more about the difference between brackets, parentheses and quotation marks.
When to Use Parentheses
# 1. Use parentheses when you want to add extra information, but be very careful with the grammatical structure of the sentence.
Remember that, if you remove the parentheses, your sentence should still both make complete sense and be grammatically correct.
So, the sentence “My best friend (and his parents) traveled to Belgium last spring” is acceptable. However, the sentence “My best friend (and his parents) have recently been to Belgium” is not and should be adjusted; for instance, you can remove the parentheses altogether.
Additionally, remember that the parenthetical information is not part of the subject. Therefore, the sentence above should be, “My best friend (and his parents) has recently been to Belgium” because the verb is only affected by the subject (my best friend), not by what is given in parentheses.
#2. When using parentheses, you should keep in mind all the other punctuation marks that surround them. If the parenthetical material goes at the very end of the sentence, the closing punctuation mark needs to go after the parentheses.
- For example: Whenever she was happy, she started to draw (and she drew all the time).
However, if the parenthetical material can stand on its own as a sentence, the closing punctuation mark can stay inside the parentheses.
- For example: John’s parents were absolutely sure that his son was studying for his upcoming exams all afternoon. (Don’t tell them that he actually sneaked out to plan a surprise party for his little sister.)
#3. The next rule applies to parentheses that appear in the middle of the sentence. If there are any punctuation marks that surround them, they never go inside the parentheses.
- For example: After we found out that he was a lawyer (he graduated from Cambridge just two years ago), his words started to make way more sense.
Notice that the comma stays outside the parentheses, in the place where it would have been if there were no parentheses in the sentence at all.
It is possible that the parenthetical material is a question, while the whole sentence is just a statement. In this case, a question mark is needed inside the parentheses, and a full stop is needed at the end of the sentence.
- For example: She got me a helicopter ride voucher for my birthday (how cool is that?).
#4. Parentheses can also be used to provide the full term of an acronym or an abbreviation.
- For example: At 25, she became the youngest CFO (Chief Financial Officer) this company has ever had.
The opposite would also work, i.e. an abbreviation can go inside the parentheses after the full term is given.
- For example: The American Psychology Association (APA) is an organization that represents psychologists of the United States of America.
#5. One other reason to use parentheses is if you want to specify the year of birth and the year of death of someone.
In this case, when you mention this person in your writing for the first time, you can include this information in parentheses right after his or her name.
- For example: William Shakespeare (1564–1616) is believed to be the best British author who ever lived.
#6. Finally, you can use parentheses to give short translations in unquoted text.
- For example: The only French words he knew were merci (thank you) and, for some weird reason, fraise (strawberry).
Parentheses within Parentheses
Sometimes, you might have to use parentheses within parentheses. According to the APA style, in this case, you will need to create these two levels of enclosure by using brackets inside of parentheses.
- For example: (We have also looked at the study that found the amount of time teenagers spend on their phones each week [N. Iqbal, 2018], but these results are not mentioned here).
With mathematical equations, however, it works the other way around: for two levels of enclosure, parentheses go inside brackets. For three levels, curly brackets can be added outside.
- For example: The students were asked to solve the following equation: 7[2x+1(x+5)]=1470.
Period Inside or Outside Parentheses?
1. If the entire sentence is inside the parentheses → period goes inside.
Example:
- (I forgot to bring my keys.)
- (This is an additional note.)
Because the whole sentence is inside the parentheses, the punctuation stays inside.
2. If only part of the sentence is inside parentheses → period goes outside.
Example:
- I forgot to bring my keys (again).
- She moved to Canada last year (in May).
Here, the main sentence is outside the parentheses, so the period stays outside.
Learn more:
- Round Brackets or Parentheses ( … )
- Curly Brackets or Braces { … }
- Square Brackets or Brackets [ … ]
- Angle Brackets or Chevrons < … >