- Books, Literature, and Writing
4 Easy Punctuation Rules for Using Commas
To Use or Not to Use
That is the question! My college students have trouble using commas correctly and you might have trouble too. To help, I've written this simple guide for the 5 most important reasons you need a comma. If you memorize these rules, you should be able to do it right every time.
Use Before Conjunction Separating 2 Clauses
Example: James kissed me, but he really likes Betty best.
That rule might sound difficult, but it really isn't if you understand these two words:
- Clause: a phase that has both a subject and a verb (which makes it a sentence, no matter how short). Simple Clauses: Jeremy jumped. Ricardo ran. Mercedes twirled.
- Conjunctions: and, but, or, so, yet.
Here is the pattern: main clause,conjunction main clause.
(3 clauses) Jeremy jumped, and Ricardo ran, but Mercedes twirled!
(2 clauses) We came to class, but everyone had gone home.
(2 clauses) You left without me yesterday, yet I still managed to find someone to go home with me.
(3 clauses) Sally ate lunch with me before, so I expected she would eat with me today, but she asked Violet to sit by her instead.
(3 clauses) My friends were going to go home with me, but they didn't remember to wait until my class was finished, so I walked home alone.
How to proofread your paper for this rule:
- Circle all of the conjunctions in your paper (and, but, or, so, yet).
- Check to see if there is both a subject and a verb in the clauses on either side of the conjunction. If not, then you may not need a comma (Example: Jessica ran to the store and got ice cream. In this example "got ice cream" isn't a full sentence because it doesn't have a new subject. The subject is still "Jessica" so you don't need a comma.)
- Did you find a conjunction that is between 2 clauses? Great. Put a comma before the conjunction. (Example: Jessica ran to the store, but her mother had forgotten to give her the money for ice cream.)
- Here's a second way to check if you aren't sure. Can you put a period where the conjunction is and have the sentences still make sense? If so, put a comma.(Example: Jessica ran to the store. Her mother had forgotten to give her the money for ice cream.) That still sounds correct, so the comma works!
Students Editing Papers
Use Between Introductory Element and Subject
Example: Especially on Saturday, I like to sleep in late.
Introductory Element: a word or phrase that comes before the subject in a sentence.
Pattern: Introductory Element, subject and rest of sentence.
Notice that an Introductory Element can be just one word:
- Nevertheless, I don't think I can believe her ever again.
- Even in Chicago, I don't think people really want to eat pizza every night.
Or a very long phrase:
- Driving down the highway in a red convertible with the top down and her hair blowing in the breeze, May felt that she was finally the successful businesswoman she had always wanted to become.
How to proofread your paper for this rule
- Circle the subject in every sentence of your paper.
- Notice that there are words or a phrase before the subject? Put a comma right between that phrase and the subject. That's it!
Use a comma to separate unimportant information from the rest of the sentence.
Example: Bleary-eyed and half-awake, she stumbled into Starbucks.
"Nonrestrictive element" is the grammar term for stuff that isn't really important in a sentence. If you take out "nonrestrictive element" then you still understand the most important parts. Nonrestrictive elements can be put anywhere in the sentence (before the verb, after the verb or at the end of the sentence).
Restrictive element: Can you guess what "restrictive elements" might be? You're right. It is the part of the sentence that you have to have, like the subject and verb and any information that is needed so that the reader gets the main point.
Patterns and Examples
main clause, nonrestrictive element.
- Cheryl loves to go to Starbucks, her favorite hangout and study place.
nonrestrictive element, main clause.
- Although enjoying the free wifi and good vibes, Cheryl likes the coffee most of all.
subject, nonrestrictive element, verb and rest of sentence.
- Cheryl, my roommate in college, is fast becoming a Starbucks addict.
- Joy, my other roommate, always gets a latte because it is her favorite drink.
subject, nonrestrictive element, verb and main clause, nonrestrictive element
- Her boyfriend, whom I had just met that morning, got a steamed milk, which he didn't think was hot enough.
How to proofread for this rule:
- Look at each sentence, especially long ones.
- Think: Is the information necessary or not? If you can read the sentence without that phrase and the sentence still makes sense and says the main idea, then you need a comma to separate that unnecessary (nonrestrictive) information from the rest of the sentence.
- Another way to check is to try to add parenthesis around the information. Does that work when you read the sentence? Then that is another sign that phrase is nonrestrictive and unnecessary. Use commas.
Use a comma to separate a list.
Example: Raul brought a tent, sleeping bag, guitar, camera, and pajamas.
This is probably the easiest rule. When you have a list, you need to separate the items by a comma.
Pattern ... Item 1, item 2, and/or item 3....
I got a small flavored coffee, Swiss mocha, and two muffins, one blueberry and the other apple-cinnamon.
Cheryl bought a chocolate donut, a cinnamon bun, three donut holes, and two twists.
- You also use a comma to separate a list of describing words (adjectives) but you don't use a comma before the word the list is describing.
Pattern: First adjective, second adjective, third adjective word modified
the sticky, sweet, chocolate donut
the soft, white, fluffy inside of the chocolate-glazed, sprinkle-covered donut
When you are doing a final proofread for punctuation, it helps to read the paper out loud. Frequently, we will pause as we read if there needs to be a comma.
Instead of a comma around nonrestrictive elements, you can also use parenthesis or dashes, but those are more informal types of punctuation and they create a slightly different meaning. Here is the difference:
- Parenthesis: shows that the information is really not very important, or is another name for something.
- Dash: emphasizes the information but also gives an informal and casual feel. Dashes work best in emails and in writing that is like speaking.
Main clause: contains a subject and verb, whole sentence
Phrase: group of words which aren't a complete sentence (subordinate clause)
Introductory element: any phrase that comes before the subject
Nonrestrictive element: any phrase which is not needed, extra information
Restrictive element: phrase which is needed for the sentence to make sense