1. Commas are used to indicate a pause or a change in thought.
Comma Rules
Commas are used to indicate a pause or a change in thought.

2. Use Commas … To Separate Introductory Clauses and Phrases
Use a comma to separate an adverb clause or a long phrase from the independent clause that follows it.

3. Example
If every automobile in the country were a light shade of red, we’d live in a pink-car nation.
According to some experts, solar-powered cars will soon be common.

4. Use Commas … Between Items in a Series
Use a comma between words, phrases, or clauses in a series.(A series contains at least three items.)

5. Example
Chinese, English, and Hindi are the three most widely used languages in the world. (words)
My dad works in a factory, my mom works in an office, and I work in school. (Clauses)

6. Use Commas… In Dates and Addresses
Use commas to set off items in an address and items in a date.

7. Example
On August 28, 1963, Martin Luther King, Jr., gave his famous “I Have a Dream” speech.
The address of the King Center is 449 Auburn Avenue NE, Atlanta, Georgia

8. Use Commas… To set off Interruptions
Use commas to set off a word, phrase, or clause that interrupts the main thought of a sentence.
These interruptions can usually be identified through the following tests:
You can leave them out of the sentence without changing the sentence.
You can place them other places in the sentence without changing its meaning.

9. Example
Our school, as we all know, is becoming overcrowded again. (clause)
The gym, not the cafeteria, was expanded a while ago. (phrase)
My history class, for example, has 42 students in it. (phrase)
There are, indeed, about 1,000 people in my school. (word)

10. Use Commas… In Compound and Complex Sentences
Use a comma between two independent clauses that are joined by a coordinating conjunction (FANBOYS) forming a compound sentence. (Compound)
Use a comma after the dependent clause of a complex sentence. If the dependent clause comes before the independent clause. (Complex)

11. Example
Computers can be valuable in education, but many schools cannot afford enough of them.
Since school is out for the semester, I can stay up until midnight playing X-box.

12. Use Commas… To set off Appositives
Commas set off an appositive from the rest of the sentence. An appositive is a word or phrase that identifies or renames a noun or pronoun.

13. Example
The capital of Cyprus, Nicosia, has a population of almost 643,000. (Nicosia renames capital city of Cyprus)

14. Use Commas… To separate two or more adjectives
Use a comma to separate two or more adjectives. Use this test to help you decide if two adjectives modify equally:
Insert and between the adjectives. If the sentence reads well, use a comma when the and is left out.

15. Example
I am in a happy, jovial mood today.