The four comma rules

I love commas. I love them so much that, on occasion, I’ve been known to give a few choice students shirts that read, “I love commas” (which they never wore to class, and that was totally rude). I also love the synthesizing semi-colon and the hip em dash, but a comma used well is especially beautiful.

Of course, the opposite is true. A comma used incorrectly is like a mustard stain on a white dress. It sullies the entire sentence, paragraph, and essay.

The bad news is that most of us sat through a torturous junior-high grammar class where our lazy teachers utilized the grammar textbook in isolation, along with its 85 comma rules. Eyes glazed over, and the teacher didn’t care; she just kept assigning another page of sentence diagramming. And now society loathes grammar and still doesn’t know how to use punctuation.

The real victim, though, is the comma, who gets thrown into awkward sentences as some kind of fix-it-all or is forced to behave in ways she was told never to behave. Just imagine her shame.

When I was a senior in college—think of it, I was an English major and didn’t learn these until I was a senior in college—I finally had a fabulous teacher who embraced the comma’s innate beauty and condensed those 85 textbook rules into just four simple comma rules.

That’s right—four comma rules.

If you use these, you won’t screw up. And since there are just four, even a kid can memorize them, like, today.

Without further ado, here are the four comma rules I teach to college freshmen with much success:

Use commas to separate items in a series.

I like show tunes, fish tacos, and old houses.

Use a comma after introductory elements. That means when a word or words appear before the subject in a sentence, you ought to follow up these introductory words with a comma.

When the show finally ended, we left the theater in a hurry.

Use commas to offset extra information. That means unnecessary but helpful details or phrases should have a comma on either side (unless the information comes at the end of a sentence, in which case the period takes the place of the second comma).

My sister, who is also a great dancer, always earns straight A’s.

She lives at 2347 Toby Lane, a great street with a lot of bungalows.

Use a comma when independent clauses are connected with a conjunction.

Now don’t freak out over the grammar talk; here’s what it means: An independent clause is just a group of words that has both a subject and a verb—it truly could function on its own as a sentence. When I teach this concept, I often call independent clauses “mini sentences.” So if you have a sentence with two mini sentences connected with a conjunction like for, and, nor, but, or, yet, or so, place a comma before that conjunction.

Sarah went to the store for milk, but she forgot to buy the eggs she needed.

See how “Sarah went to the store for milk” could be a sentence? So could “She forgot to buy the eggs she needed.” This sentence has two mini sentences. And because the word “but” connects the two, it needs to arrive with a comma in front of it.

Now see how the sentence below differs:

Mike liked to ride dirt bikes but couldn’t because of his broken collarbone.

Note how this sentence does not need a comma because we don’t have two independent clauses or mini sentences. “Mike” is the only subject in the sentence—Mike liked to ride dirt bikes AND Mike couldn’t because of his broken collarbone. That means you don’t have two independent clauses; instead, you have one subject with two verbs, and you NEVER separate a subject from her verbs. Never.

Next week I’ll talk about a few common comma errors you’ll want to avoid. But if you’ve read this entire post, congrats! You’re on your way to becoming a comma expert.

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