The Comma Rules

Comma Rules

DO's

The main rule: Use commas to separate equal elements (eg, independent clauses, items in a series) and to set off modifiers or parenthetical words, phrases and clauses. See bold pink font below.

1. Separate inependent clauses joined by a coordinating conjunction.
The cat wouldn't play, and the dog wouldn't jump.
Tea had to explain, for the rules were complex.

2. Use a comma between words, phrases, or clauses in a series (this is otherwise known as the serial comma in the US).

Words
My jeans were torn, dusty, and wet. (The second comma can be omitted, as in the UK.)

If "and" is omitted, however, the second comma must remain.
My jeans were torn, dusty, wet.

Phrases
We searched for the ring in the dresser, in the ancient suitcases, and under the bed. (These are examples of prepositional phrases.)

Dependent clauses
Finally we decided that the ring had been lost, that a thief had removed it, or that it had been sold. (These are dependent clauses because each group of words separated by the commas cannot stand alone as sentencs.)

Independent clauses
We trudged to the door, Jeigh locked the room, and Brenda suggested we forget all about it. (These are independent clauses because each group of words separated by the commas can stand alone as sentencs.)

3. Use a comma between coordinate adjectives not joined by "and."

We saw a field of tall, thick, ripe corn. (These adjectives can be moved around, or "and" added between them, and still make sense; in other words they modify the noun independently.)

We saw a field of thick, ripe, tall corn. (OK)
We saw a field of tall and thick and ripe corn. (OK)

- Do not use a comma between Cumulative Adjectives.

The bride wore a pale pink jacquard gown. (These adjectives cannot be moved around and still make sense; in other words they don't modify the noun independently.)

The bride wore a jacquard pink pale gown. (No)
The bride wore a pale and pink and jacquard gown. (No)

- Set off Introductory Verbal Phrases.

Living for centuries, vampires often find the mortal world beneath their notice.
To see if his idea would work, Andre set up the program for a trial run.
After witnessing the murder, Angela fled the scene.
Because I hate politicians, I refuse to go to rallies.

(Moving an introductory phrase to the end of the sentence might not require a comma.)
I refuse to go to rallies because I hate politicians.

4. Use commas to separate Nonrestrictive Appositives, Phrases, and Clauses.
(Nonrestrictive modifiers add information but don't change the meaning of a sentence.)

Ann's first book, Eternal Embrace, will be released before Thanksgiving. (Take out the title, and the sentence remains unchanged.)

(Restrictive modifiers are necessary to a sentence and cannot be removed without changing the meaning.)

The story Romeo and Juliet has been shown on stage for centuries. (Take out the title and the sentence changes because then it becomes any story, not Romeo and Juliet specifically.)

5. Use commas with sentence modifiers, conjunctive adverbs, and out-of-sequence sentence elements.

Sentence Modifiers
"On the other hand," "for example," "in fact," "I believe," "in my opinion," "certainly," "unfortunately," "in the first place," etc.

Conjunctive Adverbs
"Besides," "consequently," "hence," "furthermore," "meanwhile," "likewise," "nevertheless," "moreover," "thus," "therefore," "still," "then," "otherwise," instead," "indeed," "accordingly," "anyway," etc.

6. Use commas with degrees and titles, and with elements in dates, places, and addresses.

Degrees and Titles
Jonas Quincy, M.D., loved to shock police recruits at autopsies.
Laura Shinn, Sr., sang so beautifully at the church choir that tears sprang to my eyes.

Dates
Monday, May 29, is the observance of Memorial Day.
July 4, 2006, is going to be a celebration to remember.

Places
New York City, New York, is not as wild as you might think... it's wilder.

Addresses
The building is located at 250 East 36th Street, New York, New York 10016. (Note: no comma before the ZIP code.)

7. Use commas for contrast or emphasis, and with short interrogative elements.

The sailor docked at the smaller quay, not the main one.
You are my new partner, aren't you?

8. Use commas for mild interjections and with words like "yes," and "no."

Well, I thought Lesley was going to race on Sunday.
Yes, the shrub proved difficult to get rid of.

9. Use commas when directly addressing someone, including the salutation in a letter.

Brenda, do you really think there is enough boinking in this scene?
Dear Jeigh, I promise I will send the check soon.

10. Use commas with expressions like "he said," "she commented," "they replied."

"I don't hate you," Ann said, "because you're not worth my time."
They replied, "You're fired!"

11. Use commas for clarity or to indicate an omission.

Lynne Truss wrote a wonderful book, Eats, Shoots & Leaves, not Eats Shoots & Leaves.
Above, the seagulls circled and dove.
I love cheese; Lesley, chocolate.


DON'T's

1. Do not use a comma between subject and verb, between verb and complement, or between adjectives and the words they modify.

2. Do not use a comma between 2 compound elements like verbs, subjects, complements, or predicates.

3. Do not use a comma before a coordinating conjunction joining 2 independent clauses.

4. Do not use a comma before "than" in a comparison, or between compound conjunctions like "as...as," "so...as," "so... that."

5. Do not use a comma after "like" and "such as."

6. Do not use a comma with a period, a question mark, an exclamation point, or a dash. These punctuation stand alone.

7. A comma can be used after a closing parenthesis, but not before an opening parenthesis.