How to Fix a Run-On Sentence

By Joel Witherington
Jun 19, 2023
4 min read

As an editor or proofreader, knowing how to fix a run-on sentence is essential. Have you ever encountered sentences that seem to go on and on forever? Or read whole paragraphs consisting of only one or two sentences? While varying sentence length can be important, a common mistake many people make is writing run-on sentences.

This post will examine:

The most common types of run-on sentences: comma splices, fused sentences, and polysyndetons
How to fix a run-on sentence

What Is a Run-On Sentence?

A run-on sentence contains multiple independent clauses without including proper punctuation. This means that two or more independent clauses appear as one sentence without being joined by a conjunction or separated by a period or semicolon.

The three most common types of run-on sentences are:

Comma splices
Fused sentences
Polysyndetons

1. Comma Splices

Sometimes referred to as a comma fault, this error happens when a comma, instead of a semicolon, separates independent clauses without the use of a conjunction.

It has been very sunny lately, I really hope it will rain soon.

She went for a walk, there was a dog there, it jumped up on her with muddy paws.

2. Fused Sentences

These run-on sentences are often the easiest to detect because they make your writing difficult to read. A fused sentence combines independent clauses without any punctuation at all.

I like that movie I want to watch it again.

My daughter likes to run outside she comes home dirty all the time.

3. Polysyndetons

When most people think about run-on sentences, they often think about polysyndetons. You form these when your sentence uses more conjunctions than it requires.

George really likes to read books and he watches a lot of movies and when he has spare time he draws pictures.

We are running a little late, so we should probably take a taxi, or we could try to walk, but I don’t know if that is a good idea because we have a lot to carry and my back is sore.

How to Fix a Run-On Sentence

While it may be easy for you to spot a run-on sentence when reviewing someone else’s work, how you fix the problem will depend on the type of error you are dealing with. Luckily, the solutions are quite simple. Here are four methods that show you how to correct mistakes:

Separate the clauses into standalone sentences.
Add a comma and a coordinating conjunction.
Use a semicolon to separate the clauses (sometimes, a colon, en dash, or em dash is appropriate).
Turn one of the independent clauses into a subordinating clause.

Remember that you can often use more than one of these four solutions to fix a specific run-on sentence.

Fixing Run-On Sentences: Examples

1. Separate the clauses into standalone sentences:

We are running a little late, so we should probably take a taxi, or we could try to walk, but I don’t know if that is a good idea because we have a lot to carry and my back is sore. ✘

We are running a little late. We should probably take a taxi or try to walk. But I don’t know if that is a good idea because we have a lot to carry, and my back is sore. ✔

2. Add a comma and a coordinating conjunction:

It has been very sunny lately, I really hope it will rain soon. ✘

It has been very sunny lately, so I really hope it will rain soon. ✔

3. Use a semicolon to separate the clauses:

I like that movie I want to watch it again. ✘

I like that movie; I want to watch it again. ✔

4. Turn one of the independent clauses into a subordinating clause:

My daughter likes to run outside she comes home dirty all the time. ✘

Because my daughter likes to run outside, she comes home dirty all the time. ✔

Becoming an Editor or Proofreader

If spotting errors in sentences and their structure interests you, consider checking out our Becoming A Proofreader and Becoming An Editor courses. We have many learning modules that will teach you everything you need to know about punctuation, grammar, spelling, and much more. Sign up for our free trial today.