Use commas to join two independent clauses with a coordinating conjunction (for, and, nor, but, or, yet, so):
Use a comma after certain types of introductory material. A comma should be used after:
A dependent clause preceding an independent clause:
An introductory phrase of five or more words:
A transitional word or phrase at the beginning of a sentence:
Use a comma to separate direct quotes from the rest of the sentence:
Use commas before and after the year in month-day-year dates:
Use commas before and after the state, province, or country following a city name:
Use commas for the salutation and closing of a letter:
Use commas to separate:
Three or more items in a list:
Three or more phrases in a series:
Two or more equivalent adjectives modifying the same noun:
Use a comma before and after the following interrupters (material that interrupts the flow of a sentence):
A transition in the middle of a sentence:
The name or title of a person being addressed:
Use commas to separate non-essential (or non-restrictive) modifiers from the rest of the sentence. These modifiers provide explanatory or descriptive information but do not change the meaning of the word they modify:
Note: Do not use commas around essential modifiers, that is, additional information that is necessary to the reader's understanding of the noun:
Use commas between every three digits of numbers of five or more digits (except in certain types of scientific or technical writing):
Sometimes commas are necessary to clarify your meaning even if none of the comma rules above seem to apply:
