January 11 2010

Comma Do's and Don'ts

by Barbie in Grammar

The comma is a polarizing punctuation mark, generating discussion in the newsroom and classroom alike. Everyone from copy editors to students to business professionals argue over the comma’s placement, and there are as many people who overuse commas as those who under use them. It’s safe to say that Carpenter Doc never edits a document without a missing or misplaced comma.

Thankfully, there are many standard rules for comma usage, and here are some particularly popular ones to guide your writing:


  • Include a comma between independent clauses.
  • Use a comma before an introductory phrase.
  • Use a comma to set off a nonrestrictive clause beginning with “which.”
  • Follow your style guide regarding the usage of the serial comma (comma after the conjunction in a series).


  • Include a comma between the subject and verb of a sentence.
  • Use a comma around restrictive clauses beginning with “that.”
  • Include a comma between an adjective and the noun it describes.
  • Use a comma after “and” if it is joining two subjects or verbs.