Basics of Comma Usage

Separating Clauses

Clauses are important parts of your sentence!

An independent clause is a phrase that can stand on its own; it has a subject and a verb, at the minimum, but can contain other parts of speech. Some examples are as follows:

The dog ran.

The dog sprinted circles around his person.

His person lost control of his leash.

The dog escaped.

The dog ran for senate.

The dog won the election.

His person was so proud.

When connecting two independent clauses, a writer should use a comma and a conjunction. A conjunction is a word like for, and, nor, but, or, yet, or so (FANBOYS). For example:

I went fishing with my father, but I forgot that my father is allergic to fish.

I caught a red herring, and my father immediately broke out in hives.

He needed immediate help, or he would continue turning bright red.

We went to the nearest hospital, and we later had a good laugh about what happened.

What is frequently called dependent clause in this context is actually a phrase that cannot stand alone. If that phrase did stand alone, it would be a fragment rather than a full sentence. For example:

Are the champions.

Will keep on fighting until the end.

When connecting an independent clause and a phrase, no comma is necessary. However, a conjunction is.

Hercules lifted the boulder free from the entrance to the cave and freed the two little boys from their prison.

Megara hated tricking Hercules in such a manner but needed her freedom more than she wanted his love.

Hades desired Zeus's place atop Olympus and didn't care who died in his quest to defeat the Greek gods.

Separating Items on a List

In order to add clarity for a reader, a writer ought to separate items on a list.

I'm never going to give you up, let you down, run around, or desert you.

I collected six shells, two rocks, and three strands of slimy seaweed.

He searched in the basement, the attic, and the closet.

The Oxford comma is the comma that separates the second-to-last item and the last item on the list; recent discussion has cast doubt on the need for the Oxford comma. Writers need to be consistent, no matter if they use the Oxford comma or not. The following examples are also correct:

I'm never going to give up, let you down, run around or desert you.

I collected six shells, two rocks and three strands of slimy seaweed.

He searched in the basement, the attic and the closet.

Offsetting an Introductory Phrase

An introductory phrase is a phrase, word, or dependent clause, which cannot stand on its own, that introduces the independent clause that comes directly after. To separate the introductory phrase from the independent clause, a comma should be used. Some examples are as follows:

After deciding to eat his dessert before his dinner, little Jack Horner jammed his thumb into the pie.

While the ant worked hard all summer to collect food, the grasshopper played in the sun and did nothing to prepare for the coming winter.

Despite knowing the difference between right and wrong, Elliott crossed the street without using the crosswalk.

Eventually, I lost my temper, flipped the game board, and declared myself Queen of Monopoly.

Offsetting Nonessentials

A nonessential element of a sentence is something that adds clarity but is not necessary to the essential meaning of the sentence.

For example

If I only own one dog:

My dog, Bean, is super goofy.

While you are probably very interested in his name, the meaning of the sentence wouldn't change if 'Bean' was omitted.

If I own three dogs:

My dog Driver loves sleeping on my pillow.

In this case, the name of the dog is essential to clarifying my point. Because I have three dogs, I need to specify which dog this sentence is about.

Think of the commas as handles; if you were to grip those handles and lift the content out, would the sentence still have its essential content?