When Do I Use A Comma?

By Holly Michaelsen

Do you ever wonder if you’re using the comma in the right place?

These handy charts might be just what you need for quick-reference on the matter. For more detailed explanations and specific applications, please see our resource links (The University of Chapel Hill, The OWL at Purdue) and homegrown handouts (“Commas“, “Comma Splices and Fused Sentences“).


Comma Rule Example
In a compound sentence, the comma falls before a coordinating conjunction. (FANBOYS: for, and, nor, but, or, yet, so) I like ice-cream, and chocolate is my favorite flavor.
When a dependent clause comes before the independent clause, you must follow it with a comma. Subordinators often begin dependent clauses.

Sample Subordinators: because, since, when, while, until, if, as, though, although, unless, after, before, once, whether

Although I just ate, I still feel hungry.

Until mother arrives, we must wait for dinner.

In academic writing, the Oxford Comma falls before and in a sequence or list of items. A few existentialist philosophers are Sartre, Kierkegaard, and Nietzsche.
Introductory words, phrases, or clauses are set off by a comma from the independent clause.

Thus, the diagnosis was as positive as could be expected.

In times of need, we must pool our resources to survive.

Under these conditions, the bacteria reproduce exponentially.

Non-restrictive clauses are set off by commas because they add more information to what they modify without changing the meaning of the phrase. If the clause can be removed, and the phrase still makes sense, it is nonrestrictive. The two athletes involved in the skirmish, who have been injured, are going to need physical therapy to recover.
Non-restrictive appositives are set off by commas because they add additional information but do not change the meaning of the phrase. Pampered Chef, a line of cookware and utensils, is available for purchase at a cookware party that my friend is hosting.


 Comma Error  Example
A comma splice places a comma between two independent clauses (meaning they both have a subject and verb and can stand alone as complete sentences). Either a coordinating conjunction can be used with a comma, or the independent clauses can be separated by a period or a semicolon. Incorrect: I like ice cream, chocolate is my favorite flavor.

Correct: I like ice cream, and chocolate is my favorite flavor.

OR I like ice cream. Chocolate is my favorite flavor.

OR I like ice cream; chocolate is my favorite flavor.

Do not use a comma when a quotation is a question or exclamation within the entire phrase.

Also, no comma is used when a phrase concludes using that before a direct quote.

Rule 1: “What did he do?” asked the neighbor.

OR: “He ate the whole cake!” said his mother.

Rule 2: For a diabetic, it is imperative that “simple carbs are decreased or eliminated from the diet” (Mott 46).

Restrictive clauses are essential to the phrase, and removing them changes the meaning of the phrase. Athletes who have been injured need physical therapy to recover.
Restrictive appositives show that there is more than one item that could be connected to the subject. Lewis Carroll’s book Alice in Wonderland continues to be a classic.

(Lewis Carroll wrote other books as well.)



One thought on “When Do I Use A Comma?

  1. Pingback: #2bORnot2B: Meme of the Week – Commas Save Lives! – The Write Attitude

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.