Also called parentheses (particularly in America).
Brackets mainly separate information that isn’t necessary to the meaning of the rest of the sentence or can be used as an aside.
- She finally told him (after taking five minutes to think) that she did not understand the question.
If material in brackets ends a sentence, the full stop goes after the brackets.
- He paid me for my painting (£500).
Commas could have been used in the first example; a colon could have been used in the second example. The use of brackets indicates that the writer considered the information less important—almost an afterthought.
- Mount Everest (in the Himalayas) is the highest mountain in the world.
- There are several books on the subject (see page 120).
They can also be used to enclose a comment by the person writing:
- He was clearly very cross (not that I blamed him).
Easy way to think about it:
If what is in the brackets is taken out of the sentence, the sentence will still make sense. It can clarify meaning, help longer sentences to make sense and help to add information as an aside.
Square brackets are generally used to add words by another speaker in order to clarify a situation:
- She [the police officer] can’t prove they did it.
Students may like to watch the following video (it’s KS2 but I enjoyed it!):