Commas are the most complex punctuation mark, used at least fourteen different ways. Commas help create rhythm and clarity in writing, giving writers the ability to separate ideas and diversify sentence structures.
Terms You Need to Know to Use Commas
COORDINATE ADJECTIVES: Coordinate adjectives are two or more descriptive words that are used to describe a noun and are equal in the way they apply to the noun. If you have a bright, sunny disposition, you have a disposition that has two coordinate adjectives describing it: bright and sunny.
COORDINATING CONJUNCTION: A coordinating conjunction joins words, phrases and clauses together that are equal in weight or importance. There are only seven coordinating conjunctions:
- for
- and,
- nor
- but
- or
- yet
- so
INDEPENDENT CLAUSE: An independent clause is a phrase including a subject and a verb that expresses a complete idea or thought. An independent clause is a complete sentence.
DEPENDENT CLAUSE: A dependent clause is a phrase that includes a subject and a verb, but does not complete an idea or thought. It can be added to an independent clause to make a complete sentence.
CONDITIONAL CLAUSE: A conditional clause is a phrase that depends on certain factors or situations. Many conditional clauses have an if/then construction.
APPOSITIVE: An appositive is a word or phrase that explains another word or phrase next to it. If you say “that’s Sophie, my friend’s squirrel,” you are using an appositive to describe who Sophie is.
INTRODUCTORY PHRASE: An introductory phrase is like a dependent clause, but it doesn’t have a subject or a verb. Introductory phrases are used at the beginning of some sentences to add information that sets the scene for the rest of the sentence.
DIRECT ADDRESS: A direct address is the name of a person who is being spoken to. If you say, “Hey, Alex,” you are directly addressing Alex.
INTERJECTION: An interjection is a word or phrase that interrupts a sentence or is used as an aside. Interjections usually express emotion within writing. If you say, “Uh-oh,” in the middle of a thought or action, it is an interjection.
ABBREVIATION: An abbreviation is a shortened form of a word or phrase. Abbreviations are used in may ways and take on many forms, such as state abbreviations and abbreviations of titles like doctor (Dr.).
QUOTATION: A quotation is an excerpt of what someone has said or written that is used by someone other than the original author or speaker. Quotations are common in essays, novels, and in everyday speech.
14 Ways to Use Commas
- Separate Items in a List
- Separate Coordinate Adjectives
- Join Coordinating Conjunctions Between Two Independent Clauses
- Join Dependent Clauses
- Separate Conditional Clauses
- Separate Appositives
- Join Introductory Phrases
- Separate Direct Addresses
- Separate Interjections
- Separate Day of the Month from the Year
- Separate Numbers Over 999
- Separate Cities & Counties from States
- Set Apart Abbreviations
- Set Apart Quotations
1. Separate Items in a List
DESCRIPTION
Commas can be used to separate items that are in a list in order to make it clear that the items are separate things.
APPLICATION
To separate items in a list, simply place commas in between list items.
EXAMPLE
- My favorite animals are penguins, tigers, and puffins.
- (In this sentence, there is a list of animals that are all different, so they need to be separated by commas.)
NOTE: Within different organizations and fields, the Oxford comma (also known as the serial comma) may be used before the final item in a list. In journalism, the Oxford comma is generally not used and would not go after “tigers” in the sentence above.
2. Separate Coordinate Adjectives
DESCRIPTION
Often, you’ll want to describe a noun using multiple adjectives that equally describe the noun. These are called coordinate adjectives. If you have a bright, sunny disposition, you have a disposition that is equally bright and sunny, thus your disposition has two coordinate adjectives describing it.
APPLICATION
To separate coordinate adjectives, add commas between two or more adjectives describing the same noun.
EXAMPLE
- Llamas are soft, woolly animals.
- (In this sentence, the llamas can be described as both soft and woolly, so the adjectives need a comma between them.)
3. Join Coordinating Conjunctions Between Two Independent Clauses
DESCRIPTION
Often, for sentence variety and complexity, you’ll want to join two independent clauses (complete sentences) together. Commas can be used to combine sentences by including a coordinating conjunction, separated by a comma. What you get are two independent clauses to form one sentence.
APPLICATION
To separate coordinating conjunctions between independent clauses, put a comma after the first independent clause and before the coordinating conjunction.
EXAMPLE
- The birds ate the bananas, and the monkeys ate the birdseed.
- (In this sentence, the two pieces could be sentences on their own, but they are joined by and, which makes the comma necessary.)
4. Join Dependent Clauses
DESCRIPTION
Two create what we call a “complex sentence” (which basically means combining a dependent clause with an independent clause), you can use a comma! Commas can be used to join independent and dependent clauses in a single sentence.
APPLICATION
To join a dependent clause to an independent clause, put the comma after the dependent clause if it is the beginning of the sentence or after the independent clause if it is at the end of the sentence and shows contrast
EXAMPLES
- When Camille finishes work, she will go do jumping jacks with Krissy.
- (In this sentence, the dependent clause is in front of the independent clause, so a comma is required.)
- Harold rode his bike, although his leg is broken.
- (In this sentence, the dependent clause shows a distinct contrast between the two so the comma is needed.)
NOTE
Not all dependent clauses should be separated with a comma.
5. Separate Conditional Clauses
DESCRIPTION
A conditional clause is a phrase that depends on certain factors or situations. Many conditional clauses have an if/then construction. Commas are frequently used in these sentences.
APPLICATION
To separate a conditional clause, place a comma in between the conditional clauses
EXAMPLE
- If I had time, I would take Taekwondo classes.
- (In this sentence, the form is in an if/then construction. It could also be written in an extended form; “If I had time, then I would take Taekwondo classes.”)
6. Separate Appositives
DESCRIPTION
Commas can be use to separate appositive phrases from the rest of the sentence. An appositive is a word or phrase that explains another word or phase next to it.
APPLICATION
To separate an appositive, offset the appositive phrase with one comma or one on each end.
EXAMPLES
- My cousin’s journal, the leather one with the kraken embossed on it, is missing.
- (In this sentence, the cousin’s journal is described. The description of the journal is the appositive phrase and needs to be placed in between commas.)
- Gilbert, President of the Art Club, was so pumped to show off his new wax statue, he took a selfie with it and posted it on Instagram.
- (In this sentence, “President of the Art Club” is another name for Gilbert, making it an appositive phrase that needs separation by commas.)
7. Join Introductory Phrases
DESCRIPTION
Commas can be used to join introductory phrases to the main portion of a sentence.
APPLICATION
To join an introductory phrase to an independent clause, put a comma immediately after the phrase.
EXAMPLE
- Because he wanted ice cream so bad, Eric chased the ice cream truck for six miles.
- (In this sentence, the comma separates the first part of the sentence, which gives context and is an introductory phrase or dependent clause.)
8. Separate a Direct Address
DESCRIPTION
Commas can be used to separate a direct address from the rest of a sentence.
APPLICATION
To separate a direct address, put the comma before the direct address if it is at the end of a sentence, or after the address if it is at the beginning of a sentence.
EXAMPLES
- Derek, please pass me the rosemary.
- (In this sentence, the comma separates Derek, who is being addressed, from the request.)
- Now please pass me the olive oil, Derek.
- (In this sentence, the comma separates Derek, who is being addressed, from the request.)
9. Separate Interjections
DESCRIPTION
Commas can be used to separate interjections from the rest of the sentence.
APPLICATION
To separate an interjection, place commas around the interjection in the middle of a sentence, after the interjection at the beginning of a sentence, and before the interjection at the end of the sentence.
EXAMPLES
- Uh-oh, Amy’s gonna be panicked because I spilled pickle juice on the hamburger buns!
- (In this sentence, “uh-oh” is the interjection, and so it is separated with the comma.)
- When the parrot ate out of my hand, wow, it was exciting.
- (In this sentence, “wow” is the interjection, and it is separated by a comma on either side of the word.)
10. Separate Day of the Month From the Year
DESCRIPTION
Commas can be used in writing dates to separate the day of the month from the year, helping to make dates easier to read.
APPLICATION
To separate the day of the month from the year, place a comma after the day of the month.
EXAMPLE
- This year, Thanksgiving falls on November 24, 2016
- (In this sentence, the comma is placed between 24 and 2016.)
11. Separate Numbers Over 999
DESCRIPTION
Commas can be used to separate numbers over 999 in order to make them easier to read.
APPLICATION
To separate number over 999, place a comma between every 3 numbers, starting from the ones place (the last digit of the number).
EXAMPLE
- My brother said he has 12,256 different marbles in his collection.
- (In this sentence, the number is over 999, and so has a comma before the last 3 digits in the number.)
12. Separate Cities & Counties from States
DESCRIPTION
Commas can be used to separate cities and counties from states in order to make distinctions clearer.
APPLICATION
To separate cities and counties from states, put a comma between the city and state (or county and state) when they are listed one right after another.
EXAMPLES
- I love vacationing in Las Vegas, Nevada because there are so many shows to go see.
- (In this sentence, the comma separates Las Vegas from Nevada.)
- I have heard that traffic is crazy in Orange County, California.
- (In this sentence, the comma separates Orange County from California.)
13. Set Apart Abbreviations
DESCRIPTION
Commas can sometimes be used to set apart an abbreviation in the middle of the sentence.
APPLICATION
To use a comma with an abbreviation, put the comma after the punctuation mark ending the abbreviation.
EXAMPLE
- I am considering beginning Indecisive Eats Inc., a company to help people decide where to go out to eat.
- (In this sentence, the abbreviation comes in the middle of the sentence, so a comma is needed after the period noting the abbreviation.)
14. Set Apart Quotations
DESCRIPTION
One of the uses of a comma is to come before a quotation in a sentence. This helps clarify to the reader that someone is being directly quoted.
APPLICATION
To use a comma before a quotation, simply put a comma immediately following the word before where the quote starts.
EXAMPLES
- My roommate said, “I need to get my picture with Han Solo in carbonite.”
- (In this sentence, the comma follows the introduction to the quotation, but is placed before the opening quotation mark.”