Tiny Grammar Cheatsheet: Comma Rules
Use a comma...
to separate three or more words, phrases, or clauses being listed (→ I need to get bread, cheese, apples, and bananas.)
to separate two or more coordinative adjectives that modify the same noun, but no comma between the last adjective and the noun (→ His hands-on, direct approach earned him a lot of respect.)
to set off direct speech (→ He said, “I know.” / “I know,” he said.) Do not use a comma if the speech tag is after a question or exclamation (→ “Why not?” she asked.) More on punctuation in dialogue here.
to separate independent clauses, when they are joined by and, but, for, or, nor, so, yet. (→ I don't like the rain, but I have to walk my dog.)
to put a dependent clause before an independent one (→ When I went to sleep, the sun was already rising.) Do not use a comma if the dependent clause comes after the independent one (→ The sun was already rising when I went to sleep.)
after introductory clauses, phrases, or words that come before the main clause. (→ Yesterday, I got a new book. To all of you, good morning.)
before and after a clause that is not essential to the meaning of the sentence (→ My teacher, an old and cranky woman, yelled at me.) Do not use a comma when a clause is essential to the meaning of the sentence (→ This is not the type of sentence that requires a comma.)
to set off additional information such as geographical names/regions, years, titles, or names (→ On May 3, 2023, we found out that Kim, the CEO, had been using our paychecks to go on vacation in Madrid, Spain, with her husband, Mark.)
