Run-On Sentences

1. What is a Run-On Sentence?

A run-on sentence is a sentence that combines too many independent clauses (full sentences) without proper punctuation or connecting-words. We call it a run-on sentence because it “runs on” for too long without pausing—it is missing commas, semicolons, or conjunctions to clearly separate the ideas. Run-on sentences are also sometimes called fused sentences because they “fuse” together complete sentences, but don’t do it the right way.

Sometimes, people call a very long sentence a run-on sentence, but that’s not really accurate. Grammatically, a run-on joins two or more complete sentences without using any punctuation. Sometimes they are long, but sometimes they are short.


2. Examples of Run-On Sentences

Some run-ons are missing or misusing punctuation, or missing a word to connect the ideas:

  • Sally likes soccer she doesn’t like running.      Run-on

You can see that this sentence has too many ideas without any punctuation! We can fix it in a couple of different ways:

  • Sally likes soccer; she doesn’t like running.      Correct
  • Sally likes soccer, but she doesn’t like running.      Correct

By adding punctuation and coordinating conjunctions, we can fix the run-on. Here’s another example:

  • I woke up late I ate a muffin for breakfast then I went to school.      Run-on
  • I woke up late, so I ate a muffin for breakfast, and then I went to school.      Correct
  • I woke up late; I ate a muffin for breakfast, and then I went to school.      Correct

Without the proper punctuation and connecting words, the sentence is just confusing!


3. Missing Parts of Run-On Sentences

Run-on sentences are missing punctuation, coordinating conjunctions, or both.

a. Coordinating Conjunctions

To combine two sentences (independent clauses), you should usually use a coordinating conjunction. A coordinating conjunction, like “and,” works like a link between clauses. The seven most common coordinating conjunctions are and, but, for, nor, or, so, and yet.

  • Sally woke up late, so she missed the bus to school.

Also, you should note that then is not a coordinating conjunction—it’s an adverb. So, when combining independent clauses, you still need a coordinating conjunction (like and) before then:

  • Sally ate breakfast, and then she went to school.

b. Punctuation

Run-on sentences are often missing important punctuation marks: semicolons or commas.


Commas (,) are important punctuation marks that tell us when to pause in a sentence. They also help to separate ideas, which is a big problem with run-on sentences: they may not have a comma(s), so they keep “running on” without pausing. When you use a comma to fix a run-on, it comes before a coordinating conjunction, like this:

  • Sally went to soccer practice, and Sam went to math club.


Semicolons (;) connect sentences that are related to each other. It indicates that your sentence will continue with more information related to its first part. If you don’t want to use a coordinating conjunction, you can replace a comma and conjunction with a semicolon, like this:

  • Sally went to soccer practice; Sam went to math club.


4. Ways to Fix Run-On Sentences

We can think of a run-on as a sentence that really wants to be a compound sentence, but it is just missing some important things! A compound sentence has two independent clauses, so the first thing to do is identify those two clauses (each will have a subject and a predicate). Then we can focus on the two main problems that cause run-ons: missing commas and conjunctions, or misusing commas when there should be a semicolon. When you fix those problems, then you have a compound sentence.

a. Fixing Run-ons with Coordinating Conjunctions

A common and easy way to fix a run-on sentence is by adding a coordinating conjunction. Here’s a basic run-on sentence:

  • Sally likes blueberry muffins she eats them every day for breakfast.      Run-on

You can see that this sentence runs on for too long without being broken up at all. So, let’s use a comma and a coordinating conjunction:

  • Sally likes blueberry muffins, so she eats them every day for breakfast.      Correct

That’s better! Now the sentence is much easier to read and understand. Let’s try another:

  • Sally can’t bake muffins Sam can’t either.      Run-on
  • Sally can’t bake muffins, and Sam can’t either.      Correct

By adding a comma and the word ‘and,’ we break up the sentence so that it is clearer.

b. Fixing Run-ons Without Coordinating Conjunctions

If you don’t use a coordinating conjunction to correct a run-on sentence, then you should use a semicolon, NOT a comma:

  • Sally likes blueberry muffins she eats them every day for breakfast. Run-on
  • Sally likes blueberry muffins, she eats them every day for breakfast. Incorrect
  • Sally likes blueberry muffins; she eats them every day for breakfast. Correct

If you use a comma when you are supposed to use a semicolon, you get a “comma splice,” which is similar to a run-on sentence because it also misuses punctuation.


5. How to Avoid Run-On Sentences

As mentioned, a run-on tries to be a compound sentence, but fails! So, we can avoid run-ons by remembering how to properly write a compound sentence:

Compound Sentence = Independent Clause + (comma, conjunction) + Independent Clause
Compound Sentence = Independent clause + (semicolon) + Independent Clause

Finally, reviewing these rules can help you avoid run-ons:

A run-on sentence happens when you “run on” too long and use two or more independent clauses without pausing with a comma, coordinating conjunction, or semicolon.
You can use coordinating conjunctions (like and, but, or so) to connect independent clauses.
Commas can only connect two independent clauses if they are followed by a coordinating conjunction ( ___________, and ___________).
To combine two independent clauses without a coordinating conjunction, you need a semicolon (__________;___________.)
Using a comma instead of a semicolon to connect independent clauses causes a comma splice.


Test your Knowledge

TRUE or FALSE: A run-on sentence is just a really long sentence.



TRUE or FALSE: A run-on sentence is sometimes called a “fused” sentence.



Use a coordinating conjunction and comma to fix this run-on sentence:

Rabbits like carrots they don’t like cookies.




Use a semicolon to fix this run-on sentence:

Rabbits like carrots mice like cheese.




1 Comment

  1. Reply

    I like this !!!!!!

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