Commas

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Commas  ,

A comma causes a lot of trouble, for being such a small mark. We are never completely sure when and where to use it. We often add too many or not enough when we write, and for every rule about commas, there seem to be exceptions. Do the best you can with them, and remember that most English speakers (and writers) have the same problems with commas that you have! Click on the statement that has more information about what you want to learn.

1.  Commas are used to separate the elements in a series of three or more (pillows, blankets, and sheets). Some sources say the comma before the and is not needed. Most newspapers do not use that last comma anymore. (Both CC and Annie use that comma.)

BUT: If the list is long or has items that are thought of as one thing (even though they may look like two things), i.e., bread and butter, bacon and eggs, the comma is necessary.  If you always use the comma before the word and, you don't have to worry about the sentence being confusing. Note: The conjunction will not always be the word and. It may be or, nor, or another conjunction. The comma should still be used.  

• Mario ate a huge breakfast of toast and jam, bacon and eggs, fruit, and cereal with milk. (toast and jam, bacon and eggs, cereal with milk  are items in the series. They are each considered a separate item here. If they were written a different way (toast, jam, bacon, eggs, fruit, cereal, and milk), the meaning would be slightly different.)

• Alfie loves to dance the tango, the rumba, or the cha-cha when he goes to the club.

• When Belinda has time, she needs to pick up the mail, put gas in the car, and give the dog a bath.

• I will not go to school, I will not make my bed, and I will not kiss Aunt Tilly when she comes to visit! 

Notice that entire sentences (independent clauses) make up the last series. Usually a semicolon is used between two independent clauses when there is no conjunction (I will not go to school + I will not make my bed). But in this case since the sentences are short, they're related in meaning, and they're part of a series, the comma works very well.  (See #2 below)

2. Commas are used with the conjunctions and, but, for, nor, yet, or, so  to connect two independent clauses. An independent clause is a group of words that has a subject and a verb and expresses a complete thought. A sentence is an independent clause. Sometimes the comma can be left out ( as we did between the first two independent clauses in the example about not kissing Aunt Tilly) if the sentences are short, or are related clauses with similar structure. (In this case, every independent clause starts with "I will not".) If you are not sure whether to use a comma or not, use one; it won't be wrong. You can also use a semicolon between two independent clauses if there is no conjunction. 

Commas with conjunctions:

• I never want to visit there again, and I mean it. (comma + and)

• It snowed all night, but the sun was shining by morning. (comma + but)

• Teresa wanted to talk on the microphone and type at the same time, so she installed a hands-free chat program. (comma + so)

Semicolon 

• I never want to visit there again; I mean it.

• It snowed all night; the sun was shining by morning.

• Teresa was not able to talk on the microphone and type at the same time; she needed a hands-free chat program.  

3.  Commas set off introductory words or phrases (an introductory phrase is a dependent clause that pre-explains the main part of the sentence, or gives some background information about it.) If the introductory element is short, the comma may be left out, but only if the omission doesn't make the sentence confusing to understand. If you're not sure, leave the comma in. 

• Heading for home, he realized he had forgotten it was his wife's birthday.

• If you want to be successful, you must do your best at all times.

• Although Mark liked to have fun, he studied very hard.

• As the sun sets, the moon rises.

Note: Introductory clauses often start with adverbs like after, although, as, because, before, if, since, though, until, when, etc. Introductory words are those such as well, now, or yes that come at the beginning of a sentence. Common introductory phrases include prepositional phrases, appositive phrases, participial phrases, infinitive phrases, and absolute phrases.   

• To stay in that professor's class, everyone must write and speak. (introductory infinitive phrase)

• Swimming as fast as possible, Robert stayed ahead of the shark. (introductory participial phrase)

• A hard-working and dedicated student, Martin improves his English more every day. (introductory appositive phrase)

• The sky growing darker, the sailors hauled in the sails. (introductory absolute phrase)

• Before leaving for vacation, Michelle cleaned the house and shut off all the utilities. (introductory prepositional phrase)

4.  Commas set off parenthetical elements. A parenthetical element is that part of a sentence which can be left out without changing the meaning of the sentence. The parenthetical element is sometimes called added information. This is a difficult rule in punctuation. It isn't always easy to know if a phrase is needed or unneeded to make the meaning of the sentence clear. Note: If you omit or move the phrase or word in the sentence, does the meaning of the sentence change? If it does, the phrase or words are necessary. If it doesn't change the meaning, they are not necessary.

If a parenthetical element (an interjection, adverbial modifier, or an adverbial clause) follows a coordinating conjunction which is joining two independent clauses, there is no comma put in front of the parenthetical element.

• Mark got *top marks in his TOEFL exam, and naturally, he was proud. (no comma after and) (*top marks = the highest marks)

• My tulips didn't bloom this year, but actually, I think the squirrels ate the bulbs.  

• Her relatives visit her much too often, so frankly, she is sick of them.

• A *top toreador spends many years honing his craft, and even though he may have a short career, he feels it is worth the effort. (*"top" in that sentence means "the best". If you say "That computer technician is tops.", it means that the computer tech is the best of all computer techs.)

 5.  Commas separate two adjectives when the word and can be inserted between them.

• He is a tall, handsome man. (He is a tall and handsome man. sounds fine either way.)

• Rod bought an expensive second car. (you wouldn't say an expensive and second car)

• Bertha lived in a bright red house. (not a bright and red house)

• Jana loves dark, rich chocolate. (Jana loves dark and rich chocolate; fine either way.)

Commas are sometimes used when a word ending in ly is used with another adjective. To be sure that an ly word is truly an adjective, see if it can be used when it's the only word in front of the noun. If it makes sense, add the second adjective, and put a comma between the two adjectives.   

• Troy is a friendly, funny guy. (Troy is a friendly guy sounds perfectly correct. Friendly is an adjective in this sentence.) 

If the sentence doesn't make sense, don't put a comma between the two adjectives.

• I get nervous when walking on a dimly lit street. (The words "a dimly street" make no sense at all! Dimly is not used as an adjective modifying street in this sentence. It's an adverb, modifying the word lit.)

 6.  Set off short direct quotations with commas.  

Commas are used to separate quoted material from the rest of that part of the sentence that explains or introduces the quote.

• "To be or not to be," said Hamlet, "that is the question."

• "Dooby dooby doo," sang Frank Sinatra.

• Many years ago, a famous philosopher stated, "I think, therefore I am."

• "I need another dog," CC said. "How much is that doggy in the window?" 

NOTE: This quote is two sentences, with the attribution after the first sentence. Be sure you use a period after the attribution and not a comma!

If a quote is preceded by the word that, do not use commas to set it off.

• The Beatles sang that "Happiness is a warm gun. . ."   

Note: A colon is used to set off longer quotes. (See Punctuation/Colons)

7.  Use commas to set off contrasting parts of sentences.  

• I ordered pie, not cake.

• Pete says he will sing jazz, not opera.

• It was her beauty, not her good manners, that he loved.

• Babies are sweet, but they're a lot of trouble.

(Some sources say you may omit the comma that sets off a contrasting phrase beginning with but.)

8.  Use a comma to avoid confusion.

• Correct:   For many, the party was over.

• Incorrect: For many the party was over.

• Correct:   Outside, the walls of the house were shaking.

• Incorrect: Outside the walls of the house were shaking. 

• I wanted a sofa that was red and white, and blue was the color he preferred.  (Without the comma between the word white and the word and, the sentence can  be easily misunderstood: "I wanted a sofa that was red and white and blue was the color he preferred. The reader will think the sentence means that the person wanted a sofa that was red, white, and blue. The writer of that sentence "wanted a sofa that was red and white". Someone else preferred it to be blue.)

A clause beginning with because is often difficult to categorize. Is it necessary, or is it extra unneeded  information? Usually, a because clause is needed and should not be set off by commas. 

• Whitney had to take a break from class because she had started teaching her own class.  

• The ocean liner sank because it rammed into the iceberg.

 Be sure the meaning of the sentence is clear. (As you know, there are always exceptions to the rules.)

• Correct:   I know he didn't sell his house this week, because his neighbor told me.  

• Incorrect: I know he didn't sell his house this week because his neighbor told me. (Was the neighbor having told me the reason he didn't sell the house? That's not the correct meaning of the sentence. A comma is needed to make the meaning clear.)

 9.  Set off expressions that interrupt the flow of the sentence. 

• Mario is, as you can guess, a native Italian speaker.

10. Commas are used to separate a statement from a tag ending.

• You know how to whistle, don't you?

Other times to use commas:

• to surround the name or title of someone being addressed directly.

I'm sorry, Officer Kopnik, I won't speed again.          

Doug, would you please hold this for a minute?

• to separate the day of the month from the year, and the rest of the sentence.  

                     The world changed on June 28, 1914, in Sarajevo, Bosnia.

NOTE: If the month, the date, or the year is omitted, don't use commas. "The world changed in June 1914. . ."  

• to separate the city from the state, and the rest of the sentence.  

                     Travis has visited Seattle, Washington, twice in five years.  

• When the state is used as a possessive form, don't add a comma after it.

                     Seattle, Washington's skyline boasts the famous Space Needle. 

• to surround degrees or titles used with names. 

                        Dr. Hannibal Lector, M.D., loved liver.

Worth Remembering

There are a lot of reasons for using commas, and many (maybe most) people make mistakes using them. The biggest mistake is to use too many commas, so try not to use a comma unless you find a specific rule saying that one can be used.

Checking your work for proper comma usage

Compound Sentences

Look for the conjunctions and, nor, but, so, for, or, yet. Stop and check to see if there's an independent clause (complete sentence) before and after the conjunction. If there is, use a comma before that conjunction.

• Samuel watched television for hours, and he didn't get any sleep at all.

• Mexico is much hotter than Canada is, but Canada is much colder and rainier than Mexico is.

Comma Splices

Check your work by stopping at every comma to see if it's needed. If there's an independent clause (a complete sentence) before and after the comma, change the sentence in one of the following ways: 

1. Reword the sentence so that one clause is a dependent clause.

2. Add a conjunction after the comma.  

3. Replace the comma with a semicolon.  

4. Make two separate sentences from the joined independent clauses.