Should period (full stop) be inside or outside brackets?

Question

If some part of the sentence at the end is enclosed in brackets, should the full stop be inside or outside the bracket?

I need to visit the supermarket to get some fruits, groceries and clothes (and also to meet my friend who works there).

OR

I need to visit the supermarket to get some fruits, groceries and clothes (and also to meet my friend who works there.)

Note: The example is only to illustrate the question.

I have seen both usages, and did not find any place where such a rule is described.

Answer 1

The easiest way to make sure you do this the right way is to mentally remove the entire parenthetical portion. Then ask yourself, is the sentence still punctuated correctly?

In this case, we have a problem (because I've put the period inside the parentheses.)

In this example, everything is fine (because the period is still at the end of the sentence).

(This one is very awkward, because the exclamation point is left all by itself)!

(A parenthetical statement without any other text should include the period inside the parentheses.)

The first and third sentences are incorrectly punctuated, for the reasons explained in the sentences themselves.

Answer 2

In your example, the period goes outside the parentheses, as in the following example:

I love punctuation (bearing in mind, of course, that everybody else does, too).

In the following example, anyway, the period is inside the parentheses.

I love punctuation. (Anybody who cares about civilization loves it, too.)

Comma sense, a fun-damental guide to punctuation (Richard Lederer and John Shore), the book from which I have taken these examples, says:

Periods belong inside parentheses that enclose a freestanding sentence and outside parentheses that enclose material that is not a full statement.

What I reported is probably how the punctuation is used in American English. I don't know if it is the same in British English too. (I know that American English, and British English use punctuation differently in many cases, for example periods, or commas, inside quotes.)

Answer 3

The period should be outside the final parenthesis in your sentence because it ends the sentence, not the phrase inside the parentheses. If the phrase inside the parentheses requires its own punctuation mark(s), because it's an exclamation or a question or a quotation, then the required punctuation should be inside the parentheses and the period should be outside final parenthesis:

I need to visit the supermarket (Do I really?).

It's not normal even for dialog. I usually delete the parentheses around what I initially felt were parenthetical remarks. If they're worth writing, then they probably shouldn't be parenthetical.

Answer 4

Brackets don't end a sentence, full stops do.

If the content inside the bracket is a full sentence in its own right, then it gets a full stop. The enclosing sentence (outside the brackets) also gets a full stop.

If the content inside the brackets isn't a full sentence, then the full stop does not belong inside the brackets.

You wouldn't normally see a full sentence in brackets within a sentence in written English. More common is a full sentence in brackets between two separate sentences. As per above, in this instance, the full stop goes inside the brackets.