Commas are punctuation marks that separate different parts of a sentence, such as words, phrases, or clauses. Commas can help make your writing clear, smooth, and readable, but they can also cause confusion or errors if used incorrectly. Therefore, it is important to know the basic rules and guidelines for using commas in different situations.
When to Use Commas
Some of the common situations where you should use commas are:
- To separate items in a list of three or more things. For example:
- I like apples, bananas, and oranges.
- She studied math, physics, and chemistry.
- To join two independent clauses (complete sentences) with a coordinating conjunction (and, but, or, nor, for, so, yet). For example:
- He was hungry, but he didn’t have any money.
- She loves reading, so she goes to the library every week.
- To set off nonessential or nonrestrictive information that can be removed from the sentence without changing its meaning. This can include appositives (words that rename or explain a noun), relative clauses (clauses that modify a noun), and parenthetical expressions (words that add extra information or comments). For example:
- My brother, who lives in New York, is a lawyer.
- The book, a bestseller, was very interesting.
- I think, therefore, that you are wrong.
- To introduce or end a sentence with a word, phrase, or clause that modifies or explains the main part of the sentence. This can include transitional words (words that show the relationship between ideas), introductory phrases (phrases that provide background or context), and dependent clauses (clauses that cannot stand alone as sentences). For example:
- However, I don’t agree with you.
- After the storm, the sky cleared up.
- If you want to succeed, you have to work hard.
- To separate words or phrases that interrupt or add emphasis to the flow of the sentence. This can include interjections (words that express emotions or feelings), vocatives (words that address someone or something), and question tags (short questions that confirm or check something). For example:
- Wow, that was amazing!
- John, please come here.
- You are joking, aren’t you?
When Not to Use Commas
Some of the common situations where you should not use commas are:
- To separate a subject and a verb, or a verb and its object or complement. For example:
- The dog, barked loudly. (Incorrect)
- The dog barked loudly. (Correct)
- He gave, her a gift. (Incorrect)
- He gave her a gift. (Correct)
- To separate two independent clauses without a coordinating conjunction. This is called a comma splice, and it creates a run-on sentence. For example:
- She likes coffee, he likes tea. (Incorrect)
- She likes coffee, and he likes tea. (Correct)
- She likes coffee; he likes tea. (Correct)
- She likes coffee. He likes tea. (Correct)
- To separate two dependent clauses, or a dependent clause and an independent clause, when the dependent clause comes after the independent clause. For example:
- He went to bed because he was tired. (Correct)
- He went to bed because he was tired. (Incorrect)
- Because he was tired, he went to bed. (Correct)
- To separate two adjectives that are not coordinated, meaning that they do not have the same status or function in modifying a noun. You can test this by seeing if you can replace the comma with and, or if you can change the order of the adjectives without changing the meaning. For example:
- She wore a beautiful red dress. (Correct)
- She wore a beautiful, red dress. (Incorrect)
- She wore a red and beautiful dress. (Incorrect)
- She wore a red beautiful dress. (Incorrect)
Sources for More Information
If you want to learn more about comma usage rules, you can check out some of the following sources: