A run-on sentence is an error that occurs when two independent clauses are joined without any punctuation or conjunctions. These two clauses have been run into each other end-to-end without being linked grammatically, thus the term “run-on.”


What is a run-on sentence?

A run-on (or fused) sentence consists of two or more independent clauses that have been joined without appropriate punctuation or coordinating words. Dividing a run-on sentence into concise, meaningful units can help to clarify your message.

How might this run-on sentence be divided?

  • Locate the fused independent clauses; it may help to underline the subject-verb pairs.
  • Draw a vertical line (or lines) on your paper to separate the independent clauses.
  • Use an end mark and proper capitalization to separate the independent clauses into two (or more) complete sentences.
  • Use a comma followed by a coordinating conjunction (fanboys: for, and, nor, but, or, yet, so) to separate related independent clauses.
  • Use a semicolon (;), colon (:), or dash (–) to separate related independent clauses.
  • Change one independent clause into a dependent clause and join the two clauses, using appropriate punctuation.
  • Rewrite two fused independent clauses as one cohesive independent clause.

Let’s look at an example:

Incorrect: One way to confront a problem is to seek advice it can come from someone with more life experience.

Correction A: One way to confront a problem is to seek advice; it can come from someone with more life experience.

Correction B: One way to confront a problem is to seek advice. Frequently, guidance can come from someone with more life experience.

What are some common reasons for run-on sentences?

Many factors can lead to run-on sentences. When writing quickly, for example, you may transcribe your thoughts without noticing that the sentences are running into each other.

Since punctuation and conjunctions help readers make sense of the relationships between clauses in writing, you should apply appropriate grammar and punctuation rules when revising your drafts.

This task typically requires you to proofread after you’ve gotten all your thoughts out on the page. For many writers, waiting to proofread until after drafting allows them to stay in the flow of getting thoughts onto the page.

Are run-on sentences always wrong?

In Standard American English, which is used for most formal and academic writing, run-on sentences are considered wrong.

Run-on sentences are sometimes used in poetry (the poem may be one long sentence) and creative writing descriptions to give readers a breathless or rushed feeling. They may also be used to portray a character’s anxious thoughts or emotions, or a character’s stream of consciousness, especially if that character is of a younger age.

To identify a run-on sentence,

  1. check to ensure you understand what a run-on sentence is
  2. identify all the independent clauses in the sentence
  3. check to see if there are any punctuation marks or conjunctions linking the clauses together.

1. First, identify all the independent clauses in the sentence. You can tell you have an independent clause if you have a subject followed by a verb. You can think of the subject and verb as an actor and action. 

Ex: I ate cake it was delicious.

Clause 1: I ate cake

Clause 2: it was delicious.

This sentence contains two subjects/actors paired with two verbs/actions, so it has two independent clauses.

2. Second, check to see if there are any punctuation marks or conjunctions linking the clauses together if your sentence contains multiple independent clauses. 

I ate cake it was delicious.

This sentence contains two subjects/actors and two verbs/actions, so it has two independent clauses. There are no punctuation marks or conjunctions linking the clauses, so this is a run-on sentence.

How can I edit a run-on sentence?

There are many options for revising run-on sentences. Here are three suggestions for revision:

  • Add a period or semicolon. This separates the independent clauses into two complete sentences.

I ate cake it was delicious.

Revised: I ate cake. It was delicious.

Revised: I ate cake; it was delicious.

  • Add a comma and a coordinating conjunction (for, and, nor, but, or, yet, so). This shows the relationship between the independent clauses.

I ate cake it was delicious.

Revised: I ate cake, and it was delicious

  • Restructure the two independent clauses. Combine the clauses so that they become a single independent clause or a combination of dependent and independent clauses.

I ate cake it was delicious.

Revised: I ate delicious cake.

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