What is a Comma Splice and How Do I Fix It?

Katie Almeida Spencer
Post by Katie Almeida Spencer
Originally published February 15, 2022, updated February 15, 2022
What is a Comma Splice and How Do I Fix It?

A comma splice is the most common way to form a run-on sentence. It happens when you combine two complete sentences with a comma instead of a period. It’s super common in text messages or social media posts. 

So, it makes sense that it would spill over into business writing, particularly emails or in messaging apps like Slack. But, this doesn’t make it correct. A run-on sentence created by a comma splice is poor grammar and can negatively impact your professionalism. 

What is a run-on sentence?

A run-on sentence (also called a fused sentence) happens when two independent clauses are combined as one sentence without the appropriate punctuation. Independent clauses include a main subject and verb and usually express one complete thought. 

Here is an independent clause:

I talked to John this morning.
(
I is the subject and talked is the verb.)

Here is a run-on sentence made up of two independent clauses:

I talked to John this morning, he’s running late because his kids are sick. 

The comma should be a period:

I talked to John this morning. He’s running late because his kids are sick. 

Because a comma is used in place of a period, the original example is a comma splice.

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How a comma splice impacts your writing

Here’s the thing. Run-on sentences and comma splices don’t change the meaning of what you are saying (or in this case, writing). It’s a grammatical mistake that doesn’t impact meaning, so it can be hard to recognize or even care about them. But — and this is important — a comma splice or other run-on sentence affects your professionalism because many readers will recognize it’s wrong. 

Many people who have risen to high positions in business have not only business skills but also oral and written communication skills that convey professionalism and competency. It’s important that your writing matches your other skills, and fixing a run-on sentence structure created by comma splices is a good place to start. 

More comma splice examples and how to fix them

Here are examples of comma splices and possible ways to fix them:

  1. Diane has stepped down from the project, who wants to fill her spot?

    Diane has stepped down from the project. Who wants to fill her spot?
    (Change the comma to a period as the punctuation mark.)

  2. I don’t like team meetings, they are too long and never stay on topic. 

    I don’t like team meetings. They are too long and never stay on topic.
    (Change the comma to a period.)

    I don’t like team meetings because they are too long and never stay on topic.
    (Remove the comma and add a subordinating conjunction that shows the relationship between the independent clauses.)

  3. Jiaying has a lot of projects right now, let’s brainstorm how we can help her or take some work off her to-do list. 

    Jiaying has a lot of projects right now. Let’s brainstorm how we can help her or take some work off her to-do list. (Change the comma to a period.)

    Jiaying has a lot of projects right now, so let’s brainstorm how we can help her or take some work off her to-do list. (Keep the comma and add a coordinating conjunction to show the relationship between the independent clauses.) 

In all cases, you can simply replace the comma with a period to fix the comma splice. But, as you can see, there are a few other ways to fix these sentences as well, allowing you to add variety to your writing. Keep in mind that business writing favors short, clear, and direct sentences. 

Avoid the comma splice

A grammatical error doesn't always impact understanding but it can impact perceived professionalism. Watch out for comma-joined sentences as you edit your writing. We also strongly recommend grammar-checking services like Microsoft Editor and Grammarly. These tools help you identify comma splices, inappropriate punctuation, and other kinds of sentence errors. 

If you want to further strengthen your grammar skills, our Proofreading & Grammar Course is an excellent option. For non-native speakers of English who want extra support on their own writing, our Business Writing Techniques for Non-Native English Writers Course is a first-rate option.

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Katie Almeida Spencer
Post by Katie Almeida Spencer
Originally published February 15, 2022, updated February 15, 2022
Katie is an experienced Business Writing and English as a Second Language instructor, business writing coach, and teacher trainer. She taught Business and Academic Writing at the University of Massachusetts Boston. She holds a B.A. in Journalism from the University of Rhode Island and an M.A. in Applied Linguistics from the University of Massachusetts Boston.

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