Comma Usage

Commas serve an important purpose in sentences. Besides the period, they are one of the most common forms of punctuation. They allow us to pause quickly while reading to make sense of what is being conveyed or to take a breath when speaking.

 Some rules may be obvious to the English writer, like placing a comma after the day in a date, although it is easy to overuse or omit a comma where needed. Here are the nine most common comma usage rules to be aware of.

 Coordinate Conjunctions: They are used after and, but, for, nor, yet, and or, when these connect two independent clauses. If you add a comma between two independent clauses without a coordinating conjunction, it is called a comma splice and is incorrect.

Example: The volleyball game was cancelled, yet they still had the pizza party.

Comma Splice:  The volleyball game was cancelled, they still had the pizza party.

 Lists: Unless you are using bulleted formatting, use commas to separate different items in a sentence. Please note that the UK rule differs from the US because a comma is omitted between the last two items. There is no right or wrong, as long as you care to be consistent.

Examples: US usage: You will need eggs, butter, flour, and sugar to make the cake.

UK usage: You will need eggs, butter, flour and sugar to make the cake.

 Non-Restrictive Clauses: Add a comma before extra or non-essential information and after phrases like such as, otherwise, and which.

Example: Many water sports are offered at the shore, such as jet skiing, parasailing, and windsurfing.

 Multiple Adjectives: Include commas between adjacent adjectives within sentences.

Example: It was a cold, damp day in December.

 One-sentence Quotations: A comma is used before or after a quote in a short sentence.

Example: “A penny saved is a penny earned,” said Benjamin Franklin. (OR)

Benjamin Franklin said, “A penny saved is a penny earned.”

 Transitional Phrases: Transitional phrases connect related ideas or show contrast in a sentence. Place a comma after a transitional phrase like however, so, nevertheless, consequently, as a result, for example, and thus. 

Example of comma placement for a transitional phrase: Consequently, they could not make the trip.

Introductory Phrases: These set the stage for the meaning of the sentence. Place a comma after the introduction and before the sentence's main clause.

Example of comma placement for an introductory phrase: After her successful date with Ron, Patricia looked forward to seeing him again.

 Personal Address: In writing, add a comma after the name or noun when addressing another person or group. Add commas before and after directly addressed names added mid-sentence.

Examples: 1. Maggie, where did you park the car? 

                   2. I want you to know, Amy, that I’ll always love you.

Geographical Connection: Add a comma between two geographical names. Additional commas should be included after related geographical names in the middle of sentences.

Examples: 1. Nashville, TN, Stockholm, Sweden

                  2. I have lived in Monroe Township, NJ, for about nine years.

Like other grammatical constructions, adequate comma placement is important because it reflects your writing ability and communication skills, which will impact your credibility with an audience. Without the necessary pauses, your message can become skewed, leading some readers to become frustrated and lose faith or interest in your message. There are many other comma usage rules not mentioned here; however, the ones above are the most common and will ensure accuracy of comma placement in all forms of writing.