The Purpose of Commas
- Place them according to convention so that your reader doesn’t get caught off guard.
- Use them to separate parts of sentences so that your reader doesn’t get confused.
- Use them to emphasize a word or phrase with that little pause.
Common Situations in Which to Use Commas
Between Independent Clauses in a Compound Sentence
- John screamed.
- She ran home after school.
- His socks were on backwards.
- John screamed, and Amy put her hands over her ears.
- She ran home after school, and her mother asked her why.
- His socks were on backwards, and he didn’t notice.
- Amy put her hands over her ears because John screamed.
- Her mother asked her why she ran home after school.
- He didn’t notice that his socks were on backwards.
Between Some Adjectives
- Her curly red hair bounced free from the tie.
- His ugly, uncomfortable cotton uniform made him sad.
- The scary huge green fleshy alien stared down at her with its teeny-tiny black eyes.
Between Items in a Series
- She played soccer, football and basketball.
- The doctor was courteous, well-spoken, and kind.
- His favorite games were chess, checkers and Monopoly.
- She ran upstairs, took her shoes off, and got into bed.
To Set off Part of a Sentence That Isn’t Strictly Necessary to the Sentence’s Meaning
- Cindy, who had blond hair, raised her hand.
- Parts of the newspaper The New York Times are behind a pay wall.
A Final Word
- The Chicago Manual of Style Online (paid subscription)
- Perfect English Grammar: The Indispensable Guide to Excellent Writing and Speaking by Grant Barrett (in Kindle Unlimited at the time of this writing)
- Punctuation Mastery by Shani Raja (Udemy course)
If there is a comma situation that confuses you but that I didn’t cover in this post, please let me know what it is in the comments.