One of the most used, misused, and abused punctuation is the comma. We use them in almost every sentence we write. We can also see them in almost every sentence we read. And a lot of them have scattered around the Internet—often, in the most inappropriate way of using them. I have seen so many posts such as “where, are, you?” or “,,,that is so cool,,,” or “see you, later,,”. Yes, they might not be real posts, but you get the idea.
Then, how do we use commas?
The comma, aside from its technical uses in mathematical, bibliographical, and other contexts, indicates the smallest break in sentence structure. Especially in spoken contexts, it usually denotes a slight pause. In formal prose, however, logical considerations come first. Effective use of the comma involves good judgment, with ease of reading the end in view.
Here are some rules that might help you get yourself familiar with the uses of comma (note that these rules are based from the Chicago Manual of Style, 16th Edition):
1. Series and the Serial Comma
A. Comma Needed
Items in a series are normally separated by commas. When a conjunction joins the last two elements in a series, a comma—known as the serial or series comma or the Oxford comma—should appear before the conjunction. Chicago strongly recommends this widely practiced usage since it prevents ambiguity.
The owner, the agent, and the tenant huddled together in a corner.
I want no ifs, ands, or buts.
Paul put the kettle on, Don fetched the teapot, and I made tea.
B. Comma Not Needed
In a series whose elements are all joined by conjunctions, no commas are needed unless the elements are long and pauses are helpful.
Is it Snodgrass or Shapiro or Brooks?
Don’t forget to get me some apples and lemons and cherries.
2. Introductory Words and Phrases
A. An introductory participial phrase should be set off by a comma unless the sentence is inverted and the phrase immediately precedes the verb.
Happy with the results of her exam, she skipped and hopped and leaped all the way home.
Disgusted at what had happened in the conference room, the boss fired his secretary.
but
Running along behind the wagon was the archduke himself!
B. An introductory adverbial phrase is often set off by a comma but need not be unless misreading is likely. Shorter adverbial phrases are less likely to merit a comma than longer ones.
Today I turn three years old.
At midnight she turns to a vampire.
C. Adverbs and adverbial phrases that introduce a main clause are best not followed by a comma if they are restrictive and modify the verb in the clause. Otherwise, if they function more as an interjection, putting a comma after it is a good idea.
Eagerly she opened her gift.
Slowly they descended the stairs.
Before the footlights stood one of the most notorious rakes of the twenty-first century.
Out of the Mercedes stepped the woman we were looking for. (verb follows immediately)
but
Luckily, I’ve brought my extra credit card.
Finally, the movie we’ve been waiting for is showing in theaters.
3. Dialogues and the Likes
A. Oh and Ah
“Oh” and “ah” takes commas depending on pause.
Oh, what a beautiful morning.
Oh no! Ah yes! Oh yeah?
Oh mighty king! O mighty king!
B. Direct Address
A comma follows names or words used in direct address.
“Mr. Jones, will you please take a seat.”
“Friends, I am not here to discuss personalities.”
“Hey, baby, got some wine?”
C. Yes, No, and the Like
“Yes,” “no,” and the like generally need commas.
No, that item is not on the agenda.
Well then, we shall have to take a vote.
No no no! Never do that. (no pause in the reading)
To answer your three questions: no, no, no. (with pauses)
Hahaha! That is so funny. (no pause in the reading)
Ha, ha, ha. Don’t make me laugh. (pauses are needed to indicate sarcasm)
4. Interjections and Descriptive Phrases
A. Parenthetical Elements
Parenthetical elements need comma in slight breaks; parentheses or em dash otherwise.
An adverb essential to the meaning of the clause should not be enclosed in commas.
This, indeed, was exactly what Scali had in mind.
Two students cheated and were therefore disqualified.
We shall, however, take up the matter at a later date.
B. Restrictive and Nonrestrictive Phrases
Nonrestrictive phrases need commas; restrictive phrases don’t. A phrase that is restrictive means that it is essential to the meaning of the noun it belongs to.
The woman wearing a red coat is my sister. (Which woman? The woman wearing a red coat.)
My sister, wearing a red coat, set off for the city. (Whether she is wearing a red or a blue coat, she will always be the sister.)
5. Independent Clauses
A. Conjunctions Between Clauses
When independent clauses are joined by coordinating conjunctions—for, and, nor, but, or, yet, and so—a comma usually precedes the conjunction. If you find it hard to remember all these conjunctions, the word FANBOYS will help you remember them.
Everyone present was startled by the news, and one man fainted.
The bus never came, so we took a cab.
He gave his mom a car, and his mom gave him house.
Below, the clauses are short and closely connected; thus, the comma may be omitted.
Timothy played the guitar and Betty sang.
NOTE: Some conjunctions function can function both as subordinating and coordinating conjunctions. One example is so. If you can substitute so with so that when reading the sentence, it is used as a subordinating conjunction.
You need to have an education so [so that] you’ll have a better future.
B. Parenthetical Element before a Conjunction
When a parenthetical element—an interjection, an adverbial modifier, or even an adverbial clause—follows a coordinating conjunction used to connect two independent clauses, we put a comma before the conjunction and after the parenthetical element. But when a parenthetical element follows a coordinating conjunction used to connect two words or phrases within the same independent clause, we put a comma after the conjunction and after the parenthetical element.
The Red Sox was leading the league at the end of May, but of course, they always do well in the spring.
but
The Red Sox joined the games in spring and, as expected, won.
C. Compound Predicate
A comma is not normally used between the parts of a compound predicate—that is, two or more verbs having the same subject, as distinct from two independent clauses—though it may occasionally be needed to avoid misreading or to indicate a pause.
He had accompanied Tim and had volunteered to write the report.
She recognized the man who entered the room, and gasped. (to indicate a pause and avoid misreading [it was she who gasped, and not he man])
6. Dependent and Relative Clauses
A. omma Preceding Main Clause
A dependent clause that precedes a main clause should be followed by a comma.
If you turn around now, I will stab you to death.
B. Comma Following the Main Clause
A dependent clause that follows a main clause should not be preceded by a comma if it is restrictive, that is, essential to the meaning of the main clause. If it is merely supplementary or parenthetical (nonrestrictive), it should be preceded by a comma.
We will agree to the proposal if you accept our conditions.
She ought to be promoted, if you want my opinion.
The use of subordinating conjunctions (because, as, since, so, while, although, though, till, unless, until, etc.) will make one of the two clauses in a sentence dependent on (or subordinate to) the other (main) clause. When these are used to separate two clauses (a main clause and a dependent or subordinate clause), no comma is needed.
I want you to stay because the company needs you.
He was promoted since he’s the most qualified.
but
Because the company needs you, I want you to stay.
Since he’s the most qualified, he was promoted.
C. Relative Clauses
A relative clause that is restrictive—that is, essential to the meaning of the sentence—is neither preceded nor followed by a comma. But a relative clause that could be omitted without essential loss of meaning should be both preceded and (if the sentence continues) followed by a comma. Although which can be used restrictively, many careful writers preserve the distinction between restrictive that (no commas) and nonrestrictive which (with commas).
The book I have just finished is due back tomorrow. (Which book?)
This book, which I finished last night, is due back tomorrow.
7. Two or More Adjectives Preceding a Noun
A. Cumulative vs Coordinate Adjectives
When the adjectives used are cumulative, they follow a certain order and are not separated by a comma [to learn the specific order of adjectives, click here]. When the adjectives used are coordinate (i.e., belonging to one classification), they need not follow a certain order and are separated by a comma. Note that cumulative and coordinate adjectives might be used together to modify a noun.
Shelly was driving a beautiful old Italian touring car.
On her way to the conference, he met several enormous young American basketball players.
She was given four gorgeous, expensive long-stemmed red roses.
To get to our house, just follow the long, winding road.
B. Repeated Adjectives
When an adjective is repeated before a noun, a comma normally appears between the pair.
You’re a bad, bad dog.
Many, many people have enjoyed the book.
8. Separating Homonyms
For ease of reading, two words that are spelled alike but have different functions may be separated by a comma if a slight pause is intended.
Let us march in, in twos.
He gave his life that that cause might prevail.
9. Dates and Addresses and Place-Names
A. Dates
In the month-day-year style of dates, the style most commonly used in the United States and hence now recommended by Chicago, commas are used both before and after the year. In the day-month-year system—sometimes awkward in regular text, though useful in material that requires any full dates—no commas are needed. Where only month and year are given, or a specific day, neither system uses a comma.
The ship sailed on October 6, 1999, for Southampton.
See his journal entries of 6 October 1999 and 4 January 2000.
In March 2003 [a comma may be placed here for a slight pause following the adverbial phrase] she turned seventy.
On Thanksgiving Day 1998 [a comma may be placed here for a slight pause following the adverbial phrase] they celebrated their seventy-fifth anniversary.
B. Addresses and Place-Names
Commas are used to set off the individual elements in addresses or place-names that ar run into the text. No comma appears between a street name and an abbreviation such as SW or before a postal code.
743 Olga Drive NE, Ashtabula, OH 44044, on May 2.
Waukegan, Illinois, is not far from the Wisconsin border.
The plane landed in Kampala, Uganda, that evening.
Ms. Spiegel has lived in Washington, DC, all her life.
10. Other Useful Rules for Use of Comma
A. Comma with Parentheses and Brackets
When the context calls for a comma at the end of a material in parentheses or brackets, the comma should follow the closing parenthesis or bracket. A comma never precedes a closing parenthesis.
Although he rejected the first proposal (he could not have done otherwise), he made it clear that he was open to further negotiations.
Conrad told his assistant [Martin], who was clearly exhausted, to rest.
B. Comma with Questions
A direct question included within another sentence is usually preceded by a comma; it need not begin with a capital letter, but if the question is relatively long or has internal punctuation, an initial capital helps. An indirect question takes no comma.
Suddenly he asked himself, where am I headed?
The question, how are we going to tell her? was on everyone’s mind.
Legislators had to confront the issue, Can the fund be used for the current emergency, or must it remain dedicated to its original purpose?
but
What to do next is the question.
C. Comma to Indicate Elision
A comma is often used to indicate the omission of a word or words readily understood from the context.
In Illinois there are seventeen such schools; in Ohio, twenty; in Indiana, thirteen.
Thousands rushed to serve him in victory; in defeat, none.
The comma may be omitted if the elliptical construction is clear without it.
One student excels at composition, another at mathematics, and the third at sports.
Jasper missed her and she him.
D. Quotations, Maxims, and Questions
Comma with Quoted Material
Quoted material, if brief, is usually introduced by a comma; if longer or more formal, by a colon. If a quotation is introduced by that, whether, or a similar conjunction, no comma is needed.
It was Emerson who wrote, “Blessed are those who have no talent!”
She said, “Why?”
He is now wondering whether “to hold, as ’twere, the mirror up to nature.”
Comma with Maxims and Such
With maxims, proverbs, mottoes, and other familiar expressions, commas are used or omitted in the same way as with appositives and quotations. Whether such expressions are enclosed in quotation marks depends largely on the syntax of the sentence in which they appear.
The motto “All for one and one for all” appears over the door.
Tom’s favorite proverb, “A rolling stone gathers no moss,” proved wrong.
Comma with Questions
A direct question included within another sentence is usually preceded by a comma; it need not begin with a capital letter, but if the question is relatively long or has internal punctuation, an initial capital helps. An indirect question takes no comma.
Suddenly he asked himself, where am I headed?
The question, how are we going to tell her? was on everyone’s mind.
Legislators had to confront the issue, Can the fund be used for the current emergency, or
must it remain dedicated to its original purpose?
but
What to do next is the question.
E. Commas with Sentence Elements
Do not put a comma between major sentence elements, especially a verb and its object (whether direct or indirect), a verb and its subject, a preposition and its object.
Kirby, went to London last year. (incorrect)
The dog bit, its tail. (incorrect)
He gave her, a box of chocolate. (incorrect)
The sitting next to my friend, is my sister. (incorrect)
People should not throw harsh words against, one another. (incorrect)
No commas should appear in any of the sentences above.
Wonderlost 