The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
Use commas to integrate closely related information into the flow of the sentence. Use parentheses to set off supplementary information or an afterthought from surrounding text. Use dashes to be emphatic or dramatic and make additional information or an aside stand out.
Use an en dash to show a range. You can also use the word “to” or the paired expressions “from-to” and “between-and.” A hyphen is used instead of an en dash in some styles.
Both a colon and an em dash introduce new information that explains or builds upon something that precedes it. The colon is quieter; the dash is more emphatic and dramatic.
A hyphen is a short dash used to connect words and indicate that they together carry a single meaning. It can also signify a missing word, divide a word at the end of a line, or show a range.
An em dash sets off explanatory statements, an en dash signifies a range, and a hyphen connects words. An em dash is longer than an en dash, which in turn is longer than a hyphen.
Use an en dash to show a range (2001–02) or to replace the word “to” (Boston–New York flight). Also use an en dash to show a connection across words (US–Canada border).
Use em dashes to set off parenthetical statements, amplify a thought, begin a sentence with a list or a single noun and then provide an explanatory statement, or to mark asides, interruptions, and sudden turns in thought.