Run-On Sentences: What They Are and How to Fix Them

Run-on sentences contain too many ideas without proper punctuation. This common grammatical error occurs when you combine independent clauses without conjunctions, with too many conjunctions, or with no punctuation at all.

Examples of run-on sentences include:

• Jim is cold, he wants to go inside.

• My dog is playful she is also smart.

• The movie theater was dark and it was too expensive but we really wanted to see the movie so we bought tickets.

Can you find the errors in each sentence? If not, it may help to determine which type of run-on sentence you’re dealing with.

Run-on sentences range from mildly annoying to completely confusing, depending on the sentence. Once you know what type of run-on sentence you’re dealing with, however, they’re easy to fix.

A comma splice happens when a comma, rather than a semicolon, connects independent clauses. Examples of comma splices include:

• Kelly likes to cook, she makes chicken every day.

• Martin and Ellen moved in next door, they seem really nice.

• The train was late, I missed my meeting.

Joining these two clauses calls for a semicolon, not a comma. You can also improve them with a coordinating conjunction (for, and, nor, but, or, yet so). For example:

• Kelly likes to cook; she makes chicken every day.

• Martin and Ellen moved in next door, and they seem really nice.

• The train was late, so I missed my meeting.

A fused sentence mashes two main clauses together with no punctuation at all. These run-on sentences are the easiest to spot because they make your writing hard to read. For example:

• Mary likes dogs she has a beagle.

• I’m cold I want to go home.

• That’s my favorite book I don’t like the sequel.

All that's necessary to fix these sentences is to insert the proper punctuation. Like comma splices, you can use either a semicolon or a coordinating conjunction.

• Mary likes dogs; she has a beagle.

• I’m cold, so I want to go home.

• That’s my favorite book, but I don’t like the sequel.

When you think of a run-on sentence, you probably think of a polysyndeton. Polysyndeton refers to the use of more conjunctions than a sentence requires. Examples of polysyndeton include:

• We went to the park and we ate dinner and we got ice cream and when it got dark we chased fireflies.

• I went to high school with Brian but we didn’t have any classes together, so we didn’t recognize each other in college, but we figured it out eventually.

• Our flight was delayed, so we can go get coffee in the airport, or we can relax outside, or we can go shopping, or we can get another flight.

Sometimes, the overuse of conjunctions is a deliberate rhetorical choice. Most of the time, however, it's a simple error with an even simpler fix: Divide the statement into separate sentences with a bit of punctuation and commas. You can also change some of the independent clauses into dependent clauses by adding subordinating conjunctions or creating serial lists.

• We went to the park and we ate dinner. Then, we got ice cream, and when it got dark, we chased fireflies.

• I went to high school with Brian, but because we didn’t have any classes together, we didn’t recognize each other in college. However, we figured it out eventually.

• Our flight was delayed, so we can go get coffee in the airport. We can also relax outside, go shopping, or get another flight.

Run-on sentences are easy mistakes that appear in all sorts of writing, especially in first drafts and time-sensitive writing. For more avoidable writing errors, check out:

• 18 Most Common Grammar Mistakes

• Correcting Sentence Fragments: An Easy How-to Guide

• When NOT to Use an Apostrophe: Avoid Common Mistakes