Periods and Parentheses: Do Periods Go Outside Parentheses?

Periods and parentheses are common punctuation marks in the English language. A period at the end of a sentence serves as a form of terminal punctuation to mark a full stop. Parentheses house and bookend examples or additional information that may be written as a phrase (within an existing sentence) or as a complete sentence (standing on its own). Knowing when periods go inside or outside parentheses makes your writing clearer and your understanding of grammar stronger.

As a general rule, a period goes outside of the parentheses when the parenthetical phrase is an incomplete sentence sharing contextual information or examples. A period goes inside the parentheses when the parentheses contain a complete sentence that stands alone.

In the below examples, periods go inside the parentheses because the content inside represents an entire sentence:

1. 1. “You can borrow the book. (I finished it last week.)” In this example, the second sentence offers an explanation, which is often what phrases and sentences in parentheses provide. The second sentence builds on the first, explaining why the subject can lend out a book, and the period goes within the parentheses because what’s inside is a full sentence.
2. 2. “Come over at six o-clock sharp. (It’s a surprise party!)” The parenthetical sentence ending in an exclamation point helps modify the first sentence, offering additional context to clarify why the person should come on time.
3. 3. “To practice formal writing, cite all quoted material using MLA standards. (The school moved away from using APA last semester.)” Parenthetical sentences typically follow another sentence that establishes an idea, and they further explain that initial concept.
4. 4. “‘I don’t want to go to the park,’” he said. “It’s nearly dark out. (Plus it’s cold.)” This example shows how parentheses can operate within dialogue’s quotation marks. The period and closing parenthesis precede the closing quotation mark.

There are many reasons why a period might fall outside parentheses:

1. 1. “She’s had many pets (parrots, cats, fish), but she can’t have any in her new apartment.” Here, the parenthetical material lists examples of the pets the subject has kept; the period comes after the rest of the sentence because the listed animals are added information and are not a complete sentence. A comma follows the closing parenthesis to separate the sentence’s two independent clauses.
2. 2. “We will be meeting at noon (Mountain Time).” In the second example, the period goes outside the parentheses at the end of the sentence because what is inside of them offers additional information that does not form a whole sentence. Area codes for phone numbers and time zones are standard details found in parentheses. You can also place abbreviations for time zones, like MT or EST, within parentheses.
3. 3. “Italics are used freely in chapter four (page ninety-nine) to highlight that the character is finally expressing himself.” Use parentheses to share details; here, the parenthetical information states the page number of the passage.
4. 4. “For our vacation, we should buy a cooler (I think I lost mine?) and also some spices for cooking.” A parenthetical phrase with a question mark falls in this sentence to break up the text and explain why an item may need to be purchased.

Become a better writer with the MasterClass Annual Membership. Gain access to exclusive video lessons taught by the world’s best, including James Patterson, Neil Gaiman, Walter Mosley, Margaret Atwood, Joyce Carol Oates, Dan Brown, and more.