Indy's Comma Rules

A comprehensive list of comma usage rules from my friend Indy.

• Rule 1: Use commas to separate three or more words, phrases, or clauses written in a series.
• The candidate promised to lower taxes, protect the environment, and reduce crime. 
• Rule 2: Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet. 
• I have painted the entire house, but he is still working on sanding the doors. 
• Rule 3: Use commas after introductory clauses or phrases that come before the main clause, and introductory words such as well, no or yes. 
• While I was eating, the cat scratched at the door. (There's a long dead English rule that said three or more words in the introductory clause did not require a comma, so many people mess it up nowadays. But the rule now is that any introductory phrase get a comma). 
• Yes, I do need that report. 
• Rule 4: Use a pair of commas in the middle of a sentence to set off clauses, phrases, and words that are NOT essential to the meaning of the sentence. If these words are dropped, the sentence will still retain the same meaning. 
• I am, as you probably noticed, very nervous about this. 
• Rule 5: Use commas to separate two or more adjectives that describe the same noun when the word "and" can be inserted between them. 
• He is a strong, healthy man. (He is a strong and healthy man). 
• Rule 6: Use commas to set off all geographical names, items in dates, addresses, and titles in names. 
• I lived in San Francisco, California, for twenty years. (No comma is needed after the state if the state's name is abbreviated.) 
• She met her husband on December 5, 2003, in Mill Valley, California.
• They met in December 2003. (No comma is needed if the entire date is not used.) 
• Al Baker, M.D., is our doctor. 
• Rule 7: Use commas to separate a direct quotation from the rest of the sentence. 
• Mother asked, "Who wants to get ice cream?" 
• "I do," he said. 
• Rule 8: Use commas when necessary to prevent possible confusion or misreading. 
• To Steve, Lincoln was the greatest president. (This is an introductory clause, so it actually falls under that rule, but there are other instances that don't fit neatly into one of these other rules. But beware: "To prevent misreading" does not mean to add a comma whenever you pause to take a breath.) 
• Rule 9: Use commas before or surrounding the name or title of a person directly addressed. 
• Will you, Sam, have the surgery? 
• Yes, Doctor, I will. (Capitalize a title only when directly addressing someone.) 
• Rule 10: Use a comma to separate a statement from a question. 
• I can go, can't I? 
• Rule 11: Use a comma to separate contrasting parts of a sentence. 
• That's my money, not yours. 
• Rule 12: Use commas surrounding words such as therefore and however when they are used as interruptors (not conjunctions) . 
• I would, therefore, like a response. 
• I will be happy, however, to volunteer my time. 
• Mr. Baines lives in Tucson; however, his children live in Phoenix. (used as conjunction) 
• Rule 13: Comma splices. Two complete thoughts are not connected with a comma unless there is a conjunction. 
• I'm going to town, I'll be back soon. (Comma splice!) 
• I'm going to town, but I'll be back soon. (Correct usage.) 
• I' m going to town; I'll be back soon. (Not incorrect, but these two ideas are not connected closely enough to warrant a semicolon.) 
• I'm going to town. I'll be back soon. (This is the ideal way to punctuate these thoughts.)