Roane State Community College

Learning when to and when not to use commas is a difficult and sometimes overwhelming task for many writers, but it is absolutely essential because commas are signals that tell readers which words need to be separated from each other or which words are not essential to the basic structure of a sentence. Below is just a quick reference guide for the most common uses of the comma. This interactive comma and semicolon workshop will also help you to quickly learn and practice the most common comma rules.

• To separate items in a list.
  • We bought eggs, milk, and bread.
• To separate introductory words and phrases from the main clause.
  • Laughing at the stupidity of it, he stood up.
• To separate nonessential words and phrases, as well as dependant clauses, from the main clause. In this case, the sentence should still make sense if you remove the nonessential words and phrases.
  • The cat, which had just eaten the mouse, curled up to go to sleep.
  • The cat was sleepy after eating the mouse, which wasn’t surprising. [Remember that nonessential doesn’t mean unimportant, just that it’s not part of the main clause or that it is not necessary to identify the subject.]
• Before coordinate conjunctions (for, and, nor, but, or, yet, so) that link independent clauses. 
  • The cat was tired, so it curled up and went to sleep.

Here are a few of the most common mistakes writers make when using commas:

• Using commas to connect two sentences together.
  • The cat was tired, it curled up and went to sleep. [This creates a comma splice error, a type of run on sentence.]
• [Using commas in front of dependent words (subordinating conjunctions) like because, when, although, if, until, unless.]
  • The cat was tired, because it had just eaten the mouse.
• [Using commas after such as, like, or although.]
  • I like pastas although, I also like many meat dishes.
• [Using commas after but and and (coordinating conjunctions).]
  • I like pastas but, I also like many meat dishes.

Comma Dos and Don’ts

Understanding when and when not to use commas can be confusing; however, using commas correctly in our writing helps to take your writing to a more advanced level. It certainly doesn’t “make” the essay, but correct comma use definitely puts the finishing touches on written work, making it more readable for your audience.
This list of comma do’s and don’t’s will help you to learn when you should use commas and when you should leave them out. Don’t give up; practice makes perfect

Comma DOs:

• Use a comma after an introductory word or word group.
  • Finally, the car swerved to the left, avoiding the people on the sidewalk.
  • Until she noticed the handprints, the preschool teacher thought finger paints were a great idea.
• Use a comma between items in a series – even between the last two items.
  • Her favorite foods are pizza, lasagna, and spaghetti.
• Use a comma in front of a coordinating conjunction (for, and, nor, but, or, yet, so) when that conjunction joins two independent clauses (main sentences).
  • His head injury was severe, so the doctors began to worry.
• Use a comma to set off or separate nonessential words or phrases (words or phrases that aren’t necessary to identify the subject) in a sentence from the main clause of the sentence. Remember that nonessential doesn’t mean unimportant, just that it’s not part of the main clause or necessary to identify the subject.
  • Mr. Franks, my neighbor, wants to plant a garden. (nonessential phrase)
  • The contest winner, who lost three years in a row, is an example of perseverance. (nonessential adjective clause)
  • Some people, by their faith in human nature, bring out the best in others. (nonessential adjective phrase)
  • One activist, the respected W.E.B.Dubois, worked tirelessly for racial equality. (nonessential appositive phrase)
• Use a comma with transitional expressions, parenthetical expressions, contrasting elements, and absolute phrases.
  • Mr. Wilson, for example, was unable to cope from tireless touring. (transitional expression) Note: When a transitional expression joins two independent clauses, a semicolon should be used instead of a comma.
  • Mr. Wilson was unable to cope from his tireless touring; for example, he was on the verge of a breakdown when the tour finally ended.
  • Technology, so they say, is indeed the wave of the future. (parenthetical expression)
  • As an actor, Russell Brand is a comedian, not a dramatist. (contrasting element)
  • The snake slithered through the tall grass, the sunlight shining now and then on its skin. (absolute phrase).
• Use a comma to set off words of a direct address, and yes and no.
  • John, do you need some water now?
  • Yes, I will meet you at noon.Use a comma to separate a direct quote from the rest of the sentence.
• Use a comma to separate parts of dates and addresses.
  • On March 4, 1931, she traveled to Canada.
  • The President of the United States lives at 1600 Pennsylvania Avenue, Washington, D.C.

Comma DON’Ts:

• Don’t use a comma to connect two main sentences (independent clauses).
  • I like to reflect on my life, it is a necessary part of personal growth.
  • I like to reflect on my life. It is a necessary part of personal growth.
• Note: Many choices are available for sentence combining. Don’t use a comma to separate the subject and verb in an independent clause.
  • Reflecting on one’s life, is a necessary part of personal growth.
  • Reflecting on one’s life is a necessary part of personal growth.
• Don’t add a comma before the first or after the last item in a series.
  • Americans work longer hours than, German, French, or British workers, are expected to work.
  • Americans work longer hours than German, French, or British workers are expected to work.
• Don’t add a comma after “such as” or “like” or “although.”
  • I like Italian pastas such as, lasagna, spaghetti, and fettuccini.
  • I like Italian pastas such as lasagna, spaghetti, and fettuccini.
  • Women were portrayed in Elizabethan drama although, they were acted by men.
  • Women were portrayed in Elizabethan drama although they were acted by men.
• Don’t use a comma to separate compound word groups unless they are independent clauses.
  • His head injuries were so severe that the doctors became worried, and wanted to run more tests.
  • His head injuries were so severe that the doctors became worried and wanted to run more tests.
• Don’t use a comma to separate essential words and phrases from the main clause of the sentence.
  • The neighbor, who lives behind me, wants to plant a garden.
  • The neighbor who lives behind me wants to plant a garden.
  • Note: The neighbor can’t be indentified without the phrase “who lives behind me,” so this lets us know that this phrase is essential to the sentence and should not have commas around it.
• Don’t use a comma in front of dependent conjunctions (because, although, until, since, when, etc.).
  • The children need to be tested again, because the first results were unreliable.
  • The children need to be tested again because the first results were unreliable.
• Don’t use a comma between adjectives that cannot be reversed in order (cumulative adjectives).
  • Three, thirsty hikers emerged from the mountain.
  • Three thirsty hikers emerged from the mountain.
  • Note: Because we cannot reverse the order of these adjectives and have the sentence make sense, we can’t use a comma to separate them. Another tip is to try replacing the comma with “and.” If we can do this and the sentence still makes sense, then we need the comma. If it doesn’t make sense, then we need to remove the comma from the adjectives.
• Don’t use a comma between adjectives and nouns.
  • A review by a published, writer would be helpful.
• Don’t use a comma between adverbs and adjectives.
  • My house is a delightfully, chaotic environment for children.
  • My house is a delightfully chaotic environment for children.
• Don’t use a comma after coordinating conjunctions (for, and, nor, but, or, yet, so).
  • His head injury was severe so, the doctors began to worry.
  • His head injury was severe, so the doctors began to worry.