What is a Coordinating Conjunction?

It is important to understand the function of independent clauses, commas, and coordinating conjunctions in order to use this comma rule correctly. A conjunction is a word that connects two other words or groups of words together. A coordinating conjunction connects two words or groups of words that are of equal importance. There are only seven coordinating conjunctions: for, and, nor, but, or, yet, and so. The easiest way to remember these conjunctions is by remembering the acronym “FANBOYS."

What is an Independent Clause?

The technical definition of an independent clause is a group of words, containing a subject and verb, that express a complete thought. The easiest way to identify an independent clause? Try reading it aloud, and see if it can stand by itself as a sentence. For example, these would NOT be independent clauses:

• before Matt and Amy got to school that day
• because they found a hundred dollar bill on the sidewalk
• although the soldiers were weary from the long day of fighting

None of those clauses could stand by itself as a sentence. Here are some independent clauses – or clauses that can stand by themselves as a sentence:

• Matt and Amy got to school that day
• they found a hundred dollar bill on the sidewalk
• the soldiers were weary from the long day of fighting

When Should I Use a Comma?

When two independent clauses are joined by a coordinating conjunction, always put a comma before the conjunction. The comma shows that the two clauses are different ideas connected by the conjunction, rather than two parts of the same clause. For example:

• Matt and Amy got to school that day, so they didn’t hear about what happened until they came home.
• They found a hundred dollar bill on the sidewalk, but they decided to try to find its owner before they spent it.
• The soldiers were weary from the long day of fighting, yet they still found the strength to write letters home to their loved ones.

In short, always use a comma before a conjunction that connects two independent clauses. Commas show that the two clauses can stand independently of each other.

This post is part of the series: When to Use Commas: A List of Comma Rules

1. Using Commas in a Series: Basic Rules
2. Using Commas Between Independent Clauses
3. Using Commas After Introductory Elements
4. Using Commas With Non-Essential Elements
5. Miscellaneous Rules of Comma Usage