Comma Splice

How to fix one of the most common writing errors.

Mignon Fogarty
5-minute read
Episode #228


I decided to write about comma splices because my friend Scott Sigler has a book coming out this week, Ancestor, published by Crown. Over three years ago, when he was publishing an earlier version of the book with a smaller publisher, he asked me to read it for him and be as brutal as possible with my comments. The biggest problem I found was comma splices.

How to Use Commas

Commas are tricky because there are so many different ways you can use them, but one of the most common ways to use commas is to separate two main clauses that are connected by a coordinating conjunction. That just means that when you join two things that could be sentences on their own with a word such as “and,” “but,” or “or,” you need a comma before the conjunction:

Squiggly ran to the forest, and Aardvark chased the peeves.

Squiggly ran to the forest is a complete sentence, and Aardvark chased the peeves is also a complete sentence. To join them with a comma, you need the word “and” or some other coordinating conjunction. If you just put a comma between them, that's an error called a comma splice or a comma fault:

Squiggly ran to the forest, Aardvark chased the peeves. (wrong)

What Is a Comma Splice?

Comma splices seem to be Scott Sigler's biggest problem. Here's an example from page 114 of the original Ancestor book, where one of the characters is talking about a cow named Fonzie:

Sara obviously named that one, she was a sucker for those old “Happy Days” reruns. (wrong)

It's easy to see in that example why the error is called a comma splice: it's because the comma is used to splice together two complete sentences when that isn't the function of a comma.

Commas aren't meant to join main clauses all by themselves; to force them into that role is to perpetrate a comma splice.

The good news is that it's easy to fix a comma splice once you're aware of the problem. Because the two clauses are complete sentences, you can treat them that way and use a period where you had a comma.

Sara obviously named that one. She was a sucker for those old “Happy Days” reruns.

It's a period's job to separate complete sentences.


About the Author

Mignon Fogarty

Mignon Fogarty is the founder of Quick and Dirty Tips and the author of seven books on language, including the New York Times bestseller "Grammar Girl's Quick and Dirty Tips for Better Writing." She is an inductee in the Podcasting Hall of Fame, and the show is a five-time winner of Best Education Podcast in the Podcast Awards. She has appeared as a guest expert on the Oprah Winfrey Show and the Today Show. Her popular LinkedIn Learning courses help people write better to communicate better.