How to use Commas Correctly
Commas seem to be the punctuation that people have the most trouble using. While some comma rules should have been engraved in our heads at a young age, many of the rules slipped through the cracks. Comma usage is important, but it doesn't surprise me that people have so much trouble finding a place for the little guys within their writing. There are quite a few comma rules out there. Many of which, I'm betting, people have been second guessing themselves on for years. It's high time to clear up all the confusion.
1.) You should always use a comma to separate two adjectives that can be separated by the word and.
- She is an intelligent, beautiful woman. (She is an intelligent and beautiful woman).
2.) Use a comma before or surrounding a name or title when directly addressing someone.
- No, Trisha, I can't come over later tonight.
- I love you, Heather.
3.) Use a comma to separate a series of three or more words.
- Some of my favorite pastimes are hiking, swimming, and boating.
4.) When writing the date, use a comma to separate the day of the month from the year. Include a comma after the year.
- David was planning to go on vacation on July 3, 2012, but decided to wait until August instead.
5.) Use a comma to separate a city from a state. A comma should also follow the state unless a two-letter abbreviation of the state is used.
- I live in Cleveland, Ohio, and love it. — I live in Cleveland, OH and love it.
6.) Use commas around expressions that interrupt sentence flow.
- Alice, despite having slept for ten hours, was incredibly tired from the day before.
7.) Use a comma to separate two main clauses joined together by a conjunction (and, but, or, nor or so). Unless, however, both clauses are short or closely related in meaning.
- I enjoy playing soccer, but I can't stand watching it on television.
8.) Use a comma when beginning a sentence with a phrase that contains three or more words.
- In the beginning, I really enjoyed working out after classes.
9.) Use a comma after a weak clause when it begins a sentence.
- Although I'm not too happy with her, I can't ignore her forever.
10.) Always use a comma after the greeting and closing of letters.
- Dear Mrs Hubert,
11.) Use a comma when interrupting direct quotations and when introducing them.
- "Who knows," she asked, " where they left the controller."
- She calmly replied, "no."
12.) Separate a statement from a question by using a comma.
- It's entertaining, isn't it?
13.) Use a comma before and after a person's title or degree.
- Be sure to call David Wilcohlm, Ph.D., as soon as possible.
14.) Use a comma to separate contrasting parts of a sentence.
- Those are your brother's jeans, not yours.
15.) When using words like however or therefore as an interrupter, surround them with a comma.
- I don't like coffee, but I do, however, enjoy a good latte.
16.) Use a comma before and after introductory words like that is, or for example.
- I like all kinds of movies, for example, action, adventure, and fantasy.
- (a colon could also be used) I like all kinds of movies: action, adventure, and fantasy.)
Avoid comma splices
A comma splice occurs when two strong clause are combined using a comma instead of a period, semicolon, or a comma and conjunction.
- Incorrect: I like chocolate ice cream, my friend likes vanilla.
- Correct: I like chocolate ice cream, but my friend likes vanilla.
- I like chocolate ice cream; my friend likes vanilla.
Avoid run-on sentences
A run-on sentence occurs when two independent clauses are joined together with no punctuation at all.
- Incorrect: My car is almost completely out of gas we won't make it home.
- Correct: My car is almost completely out of gas, and we won't make it home.
- Purdue OWL: Commas
This resource offers a number of pages about comma use.