period with quotation marks
Where the period sits with a quotation.
Put the period inside the closing quotation mark, whether or not the period belongs to the quoted words: She said, “The file is ready.”
When the quotation ends with a question mark or an exclamation point, that mark ends the sentence, and no period follows it: Her last text read, “Where are the keys?”
When the quotation ends with an abbreviation, the abbreviation’s period also ends the sentence: The sign on the gate read “Closed until 9 a.m.”
In a quotation within a quotation, the period goes inside both closing marks: Amy said, “The note on the door says ‘Back soon.’”
When a parenthetical citation follows the quotation, the period follows the citation: The report called the delay “avoidable” (p. 14).
Technical writing sometimes puts the period outside the marks after a string to be typed exactly, such as a command, a password, or a URL, so that the period cannot be taken as part of the string. In general writing, the period stays inside even then: At the prompt, type “restart.” When a reader could take that period as part of the string, recast the sentence so the string does not end it: Type “restart” at the prompt.
See also comma with quotation marks; question mark and exclamation point with quotation marks; colon and semicolon with quotation marks; quotation marks: single / double.
Examples
Use The notice said “Sold.” (The period goes inside the closing quotation mark, although the notice itself had no period.)
Avoid The notice said “Sold”. (The period outside the quotation mark is the error: in American English the period goes inside even when it is not part of the quoted words. Write The notice said “Sold.”)
Avoid He asked, “Is the museum open today?”. (The final period is the error: the question mark already ends the sentence. Write He asked, “Is the museum open today?”)
Many British publications put the period outside unless it belongs to the quoted words.