The eight general comma rules apply to quotes, appositives, series, independent clauses, introductory clauses, nonrestrictive clauses, and direct addressing. The eighth rule is subdivided to account for dates, addresses, titles, and numbers.
The proper use of a comma can be confusing. These eight general comma rules and uses will make it easier to write cohesively. Though, remember, when writing fictional narratives, authors do have some artistic license to add in commas where there normally shouldn’t be any.
1. Use Commas With Direct Quotes
When dialogue presents the identification of the speaker, a comma is required. Identification of the speaker can be in the form of their name or pronoun (Daniel/he). Examples of Commas in Direct Quotes:
“Leave that alone,” Maggie said.
Christopher shouted, “Don’t touch my bike!”
Rebecca doesn’t like beans,” she said, “because they upset her stomach.”
Related: Punctuation When Writing Dialogue
2. Commas for Appositives
An appositive is a phrase that renames a noun preceding it. In many cases, the appositive provides information that is not essential to the understanding of what or who the noun is. Appositives usually add connective information regarding relationships. A comma should sandwich the positive if centered.
Mary, his daughter, liked to walk on the beach.
Harrold Thompson, the famous author of Wilting Leaves, died in 1892
Henrietta, John’s wife, made a cake.
3. Commas for Introductory Clauses/Phrases
An introductory clause or phrase presents the reader with a proceeding sentence of value. The comma informs the reader that the introduction has ended and that the proceeding text is the main part of the sentence.
Across the street, there is a party happening.
When Tina sang, the world listened.
In Ontario, the population is 14 million.
4. Commas for Nonrestrictive Clauses
Commas are used to enclose clauses that are not considered essential to the value of a sentence. Clauses like these are referred to as nonrestrictive. Those that are essential are called restrictive. Both types of these clauses may begin with a relative pronoun (who, whom, whose, such as, that, which). A relative pronoun serves to identify the noun or pronoun that precedes it.
An early-ripening tomato, which is orange, is not quite ready yet.
Sarah, who spent most of her time sewing, made a beautiful quilt last year.
5. Commas for Independent Clauses
The most common use for a comma is to separate independent clauses. These are clauses that can stand alone as complete sentences if separated from each other. The comma should be placed just before the coordinating conjunction (and, but, so, yet). Examples:
Don’t go outside alone, and leave the keys where you found them.
She wasn’t happy with her dad, but she listened to his instructions anyway.
Scooby ate Gina’s homework, so she started over with a new page.
6. Commas for Series and Lists
Also, a common use for commas is to separate items in a series, or list. A series can be a list of three or more individual items, phrases, or clauses. Different writing styles designate whether a serial comma, also known as an Oxford comma, should be used before the last-named item. Examples:
I ate an apple, pear, and grapes for lunch. (series of items)
Daniel walked across the hall, down the stairs, and to the office. (series of phrases)
Loretta told Jennifer that she would walk the dog, that she would clean her room, and that she wouldn’t make a mess of the place. (series of clauses)
7. Commas for Direct Addressing
During dialogue or writing that includes speech, when the speaker addresses the person with whom they are speaking, this is called direct addressing. Depending on where the identification of the listener is placed within a sentence, one or two commas may be required. The comma should always be placed after the identified person if in a sentence introduction, before and after the identified person if centered, and before the identified person if at the end of the sentence. Examples:
No, Mary, you don’t have to do that.
Mary, you don’t have to do that.
You don’t have to do that, Mary.
8. Commas For Titles, Addresses, Dates, and Numbers
There are rules that apply to the usage of commas with respect to titles, dates, numbers, and addresses as well. Below is a list of instructions and examples on how to structure dates, titles, numbers, and addresses with commas.
How to Use Commas in Titles
When writing out the titles of individuals such as doctors and lawyers, use a comma after the person’s name. Follow the name with their title. If there is more to the sentence, sandwich the title with two commas. Examples:
Loretta Davis, MD, lives in Maryland.
This belongs to Scott Travis, Esq.
How to Use Commas With Addresses
Addresses require the use of a comma to separate the street address from the city and to separate the city from a state/country.
The River Thames is in London, England.
Send fan mail to Florence Garner at 123 Street Name, Portland, OR 09897
On an envelope, this address would leave out the comma after the street address, as the city would go on the following line, as so:
Florence Garner
123 Street Name
Portland, OR 09897
How to Use Commas with Dates
When writing traditional dating styles, the year is separated from the rest of the month and the day by two commas if more text follows in the sentence. If there is no sentence, and you’re just marking a date, such as would be done at the top of a letter, only a comma after the day is necessary. Examples:
February 29, 2021, was a leap year.
February 29, 2021
How to Use Commas With Numbers
When a number is four or more digits long, it should be separated into groups of three from right to left. When writing in AP, a comma is not necessary if the number is only 4 digits long. Examples:
3,500 or 3500
400,000
4,900,873
10,500,150,900
These are the basic rules for the usage of commas when writing in American English. Using commas properly can make it easier for your readers to understand your text.
Although this list covers the eight general rules for commas, there are more extensive rules as well.
