How to Fix Run-On Sentences

Run-on sentences can be difficult to understand, even if they're very easy to write! Avoid writing in run-on sentences for clearer and better-sounding writing.

What is a run-on sentence?

It is two or more complete sentences that are joined without the appropriate conjunction or punctuation.  Independent clauses have a subject and predicate, and can stand alone.

One thing to consider: The length of a sentence doesn't matter. You can have a run-on sentence with only four words. Example: He runs she walks.

This example sentence can be fixed by simply adding "and" between the two complete thoughts. You could also make them two different sentences.

How do I fix a run-on sentence?

How many ideas are you stringing together? If there are two or more completely unrelated ideas, you have a run-on sentence. There are easy ways to fix these, however. You can use a period (.) to break apart the two independent ideas. You can also use a conjunction, such as "and", "or", "but", to show the relationship between the ideas.

Here are some examples, and how to fix them.

Lucy is a runner she goes out every morning.
Lucy is a runner(.) (S)he goes out every morning. 

When Matteo has coffee, he also has a snack he likes chocolate the best.
When Matteo has coffee, he also has a snack(.) (H)e likes chocolate the best. 

Whenever I come in late the teacher tells me off I come in early now.
Whenever I come in late the teacher tells me off(, so) I come in early now. 

I was also invited to dinner I didn't want to go.
I was also invited to dinner(, but) I didn't want to go.

Renata went to the top of the Empire State Building she said was a lot of fun.
Renata went to the top of the Empire State Building (and) she said it was a lot of fun.

Tips to avoid run-on sentences

Read your sentences out loud. Are you making your point clearly? Will someone else be able to understand what you want to say?

Long sentences do not always mean good writing. Don't put lots of ideas together without understanding their relationship.

Use connecting words carefully. While the word "and" connects two related thoughts or items, it does not connect everything. Sometimes other conjunctions like "but" or "so" can better show the relationship. Other times, it's best just to use a period.

Test your knowledge of run-on sentences

Fix these sentences using a period (.)  or a conjunction (and, but, so). Find the correct answers in the English Activities Answer Key.

1. I am feeling ill I want to go to sleep.
2. Mimouna baked a cake for the party Alex made hot chocolate.
3. She was late he didn't notice.
4. Leilani didn't make dinner she went out to eat.
5. Emily wrote a blog post it was about presidents.