Commas
How to Use Commas
Lists
Commas are used to divide a list of three or more words, phrases, or clauses. For example, it can separate nouns (person, place, thing, or idea) or verb phrases (a verb with attaching words).
- Noun Example: Anna owned a cat, a dog, and a bird.
- Verb Example: David decided to sell his car, fly to Germany, and eat sausages.
Commas can also be uses to divide a list of adjectives (describing words). Use a comma when all the adjectives describe different aspects of the noun. If you don’t know whether this is the case, try inserting “and” instead of a comma. If the sentence still makes sense, you can use the comma!
- Example: A large, hairy spider startled Miss Muffett. (“A large and hairy spider” is also correct.)
However, DO NOT use commas to separate cumulative adjectives. These are adjectives that depend on each other to make sense.
- Example: Several black clouds appeared on the horizon. (It would be incorrect to say "Several and black clouds," so you cannot put a comma between those words in this sentence.
The Oxford Comma
The Oxford comma is the name for the comma before an "and" in a list. The Oxford comma is considered optional, but Learning Services recommends using it since, in most cases, it is clearer than not using it.
Whether you choose to use the Oxford comma or not, make sure you are consistent throughout your assignments (i.e., either always use it or never use it).
Introductory and Transitional Phrases
Commas are used to separate an introduction or transition phrase (or word) at the beginning, middle, or end of a sentence.
- Example: Meanwhile, Kate made lasagna for dinner.
- Example: When I was your age, I spent most evenings at soccer practice.
- Example: Burt, on the other hand, was not interested in going for a walk.
Direct Quote or Speech
Commas are used to introduce dialogue or a direct quote from a book or source.
- Example: Laura said, “Make sure to wear your boots outside.”
- Example: Baxter writes, "There doesn't seem to be a moment in Lewis's adult life in which Dante was not close at hand and vividly present in his thoughts" (13).
Connect Two Complete Thoughts
Commas are used to connect two complete sentences when they are joined by a conjunction (and, or, nor, but, for, while, yet, so).
- Example: I wanted to go to the coffee shop, but I had to buy paper clips instead. (“I wanted to go to the coffee shop” and “I had to buy paper clips instead” are two complete sentences.)
- Example: I found a new pair of running shoes at the mall, so I could go on my hiking trip next weekend.
Appositives and Nonessential Elements
Commas are used to separate appositives (nouns or phrases that describe another noun) and nonessential information. If you don't know whether this is the case, try reading the sentence without the noun or phrase. If the sentence still makes sense, it is an appositive or nonessential information.
- Example: Bilbo Baggins loved his home, Bag End. (“Bilbo Baggins loved his home” is a complete sentence. “Bag End” is an appositive.)
- Example: The Mona Lisa, one of my favourite paintings, hangs in the Louvre. (“The Mona Lisa hangs in the Louvre” is a complete sentence - “one of my favourite paintings” is nonessential information, so it can go in commas.)
Addresses and Dates
Commas are used in formatting addresses and dates.
Example: On Friday, September 12, 1873, the first functional typewriter was sold.
Example: Tyndale University is located at 3377 Bayview Ave, Toronto, Ontario, M2M 3S4.
How NOT to Use Commas
DO NOT use a comma between the subject (the noun doing the action) and the main verb (the action).
- Incorrect: Thomas, wants to drive to Wisconsin.
- Correct: Thomas wants to drive to Wisconsin.
- Incorrect: Getting enough sleep during mid-terms, is difficult.
- Correct: Getting enough sleep during mid-terms is difficult.
DO NOT use a comma between two main verbs.
- Incorrect: I sat on the roof, and looked at the stars.
Correct: I sat on the roof and looked at the stars.
DO NOT use a comma to separate essential information.
- Incorrect: Students, who do not study, will not succeed in school.
Correct: Students who do not study will not succeed in school.
More Resources
Interested in learning more? Check out these books:
