The Curious Case of the Comma

Basic sentence principles can help writers better understand comma usage.


Commas. You love them. You hate them. And you just don’t know what to do with them. 

Most writers and even nonwriters are aware of the eternal battle over the Oxford comma — the comma used to separate items in a list. However, many are unaware of the other complex uses of the comma.

So, let’s discuss everyday comma usage and break down some specific scenarios. 

Everyday Comma Usage

As far as everyday use goes, commas can be correctly placed in the following situations:

  • Separate items in a list (this is Oxford comma usage)
  • Offset introductory phrases
  • During a direct address (such as a person’s name)

These scenarios are easily remembered, and most people correctly use commas in them. But comma use can be complicated if you don’t remember some sentence-writing basics. 

Special Comma Cases

Writers often place commas within sentences, albeit confusingly. Because of this, I want to share the one thing that helps me remember how to connect longer sentences. The one thing that helps me understand how to use commas in a sentence is understanding the difference between independent and dependent clauses. Let’s dive into that just a little more.


Editor Speak: Independent clauses include a subject and verb and are complete thoughts, while dependent clauses may include a subject and a verb, but they cannot stand on their own as complete thoughts


Understanding this helps me recognize when two independent clauses are being connected or an independent clause and dependent clause are being connected in a sentence. This is important to recognize because each scenario for combining clauses is governed by its own rules.



Connecting Two Independent Clauses

When connecting two independent clauses, these clauses should be connected with a coordinating conjunction such as and, but, or, and a comma. If two independent clauses are not connected with a conjunction and simply a comma, this is actually a comma splice and should be replaced with a colon instead.

Let’s explore an example of this:

I like apples + I want to go to the apple orchard

These are two independent clauses because they reflect complete thoughts; therefore, we would combine them with a comma and coordinating conjunction. In this example, let’s use so.

I like apples, so I want to go to the apple orchard.

If I want to forgo the comma/coordinating conjunction combo, I will connect these clauses with a colon.

I like apples; I want to go to the apple orchard.

(Though I might argue that in this example with colons, these would work better with full stops — periods.)

Connecting an Independent Clause With a Dependent Clause

Comma usage for independent clauses connected to dependent clauses is a little more complex as there are a few cases in which we can do this. For now, we will focus on one specific example of dependent and independent clause connection.

When considering dependent clauses, we must consider if the clause is necessary for clarity around the subject (noun) in the independent clause. If this information is necessary, we call this a restrictive clause. Restrictive clauses are not offset by commas; they are usually connected with the word that. Conversely, a clause that is not necessary is considered nonrestrictive and is encased in commas. These types of clauses often include the word which.

Here are some examples: (the dependent clauses are in red)

Independent Clause + Restrictive Dependent Clause

The blog post that I posted this week is about mental health awareness.

Independent Clause + Nonrestrictive Dependent Clause

My dinner, which consists of a ham and cheese sandwich, is too hot.

As writers, many of us will find that getting back to learning the basics about sentence structure, grammar, and punctuation will help us become better writers. In understanding what seems to be rudimentary principles of writing more deeply, we will find that we understand the complex issues better.

Featured photo by Tirachard Kumtanom on Pexels; in-text photo by Michael Burrows on Pexels