Commas help group ideas and categorize parts of your sentence.


Use commas:

  1. to separate a dependant clause from an independent clause: When I get home at night, I turn on the TV and eat a whole tub of ice cream.
  2. after a coordinating conjunction. These include for, and, nor, but, or, yet, and so (FANBOYS). I’m not always polite, but I mean well.
  3. to separate lists of three or more things: My favorite cookies are made with chocolate chips, butterscotch, and rolled oats
  4. to insert additional or non-essential content in a sentence: The professor, a bumbling idiot, never quite figured out how to teach the class.
  5. to separate two or more coordinate adjectives. What is a coordinate adjective? Adjectives that aren’t attached to each other and are equally important for modifying the noun. For example: “Australia” was an exceptionally long, boring movie.

Tip: test if adjectives are coordinating by adding and between them. If you can add it and it isn’t awkward, they pass the test.

Don’t use commas:

  1. between a subject and a predicate.
    • incorrect: My nose, is very large.
    • correct: My nose is very large.
  2. between two independent clauses (complete thoughts that can stand alone as sentences). What should you use instead? Try:
    • a period- this may help simplify, but can get tedious if used too often. Short sentences are good for clarity.
    • a semicolon- relieves the simplicity of a period. Add a conjunction to smooth out the sentence; leave it out for effect.
    • a comma with a conjunction- this is a good choice because it gives the sentence enough length to not insult the readers.
    • a subordinating conjunction (sc)- semicolons add a dry, formal touch, whereas sc’s flow naturally. Commas are there to help you clarify your point by grouping ideas. It’s up to you to add them where necessary for effect, but overdo them and expect a flogging from your editor.