Grammar & Mechanics

Run-On Sentences: How to Spot and Fix Them

The Humanize Team · 17 Jun 2026 · 4 min read
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Run-on sentences are a common stumbling block for writers. They happen when two or more independent clauses (complete thoughts) are joined incorrectly. The result? Confusing, hard-to-read prose that undermines your message. Let's break down what they are, how to spot them, and, most importantly, how to fix them.

What Exactly is a Run-On Sentence?

At its core, a run-on sentence is a grammatical error where independent clauses are mashed together without proper punctuation or conjunctions. Think of an independent clause as a standalone sentence; it has a subject and a verb and expresses a complete thought.

Here are the two main types of run-on sentences:

  • Fused Sentences: These occur when two independent clauses are simply placed next to each other with no punctuation at all.

Example:* The dog barked loudly the cat ran away.

  • Comma Splices: These happen when two independent clauses are joined only by a comma. A comma alone isn't strong enough to separate two complete thoughts.

Example:* The dog barked loudly, the cat ran away.

Both types create a jumble of ideas that can leave your reader lost.

How to Spot a Run-On Sentence

Spotting run-ons takes a bit of practice, but there are some key indicators.

1. Read Aloud

This is perhaps the most effective technique. When you read your writing aloud, your ear can often detect awkward pauses or a lack of separation where there should be one. If you find yourself running out of breath or a section feels like it's just one long, unbroken thought, you might have a run-on.

2. Identify Independent Clauses

Go through your sentences and try to identify each independent clause. Ask yourself: "Does this part of the sentence express a complete thought? Could it stand alone as its own sentence?" If you find two or more such clauses strung together improperly, you've likely found a run-on.

  • Example: The sun was setting (independent clause) the birds were singing their evening songs (independent clause).

* In the sentence "The sun was setting the birds were singing their evening songs," these two independent clauses are fused.

3. Look for Missing or Misused Punctuation

Pay close attention to punctuation, especially commas and periods. Are commas being used to join complete sentences? Are there sentences that seem to be missing any punctuation between distinct ideas?

How to Fix Run-On Sentences

Once you've spotted a run-on, fixing it is straightforward. There are several effective methods:

1. Separate into Two Sentences

The simplest solution is often to break the run-on into two distinct, complete sentences. Use a period to end the first independent clause and start the second one with a capital letter.

  • Original Run-On: The weather was beautiful we decided to go for a hike.
  • Fixed: The weather was beautiful. We decided to go for a hike.

2. Use a Comma and a Coordinating Conjunction

You can join two independent clauses with a comma followed by a coordinating conjunction. The common coordinating conjunctions are: for, and, nor, but, or, yet, so (often remembered by the acronym FANBOYS).

  • Original Run-On: She studied for hours she was determined to pass the exam.
  • Fixed: She studied for hours, for she was determined to pass the exam.
  • Fixed (alternative): She studied for hours, and she was determined to pass the exam.

3. Use a Semicolon

A semicolon (;) can be used to join two closely related independent clauses. It signals a stronger connection between the ideas than a period but is a clearer separation than a comma alone.

  • Original Run-On: The report was lengthy it contained vital information.
  • Fixed: The report was lengthy; it contained vital information.

4. Use a Semicolon and a Conjunctive Adverb

Similar to using a comma and a coordinating conjunction, you can join two independent clauses with a semicolon, followed by a conjunctive adverb, and then a comma. Common conjunctive adverbs include: however, therefore, moreover, consequently, nevertheless, furthermore, indeed.

  • Original Run-On: He missed the bus he had to walk to work.
  • Fixed: He missed the bus; therefore, he had to walk to work.

5. Restructure the Sentence

Sometimes, the best fix involves more than just punctuation. You might need to rephrase one of the clauses or turn one into a dependent clause.

  • Original Run-On: The new software was difficult to learn users struggled with its interface.
  • Fixed: Because the new software was difficult to learn, users struggled with its interface. (Here, "The new software was difficult to learn" becomes a dependent clause.)

Why Mastering Run-Ons Matters

Clear writing is effective writing. Run-on sentences obscure your meaning and can make you appear careless or unprofessional. By learning to identify and correct them, you enhance the readability of your work, ensuring your ideas are communicated precisely and persuasively. If you're looking for professional help to refine your writing and eliminate these common errors, EssayGazebo.com offers expert services to ensure your work shines.

Practice Makes Perfect

The key to conquering run-on sentences is consistent practice. As you write, consciously apply these techniques. Review your work, read it aloud, and don't be afraid to revise. With a little attention, you'll soon be spotting and fixing run-ons with confidence, making your writing clearer and more impactful than ever before.

Frequently Asked Questions

What's the main difference between a fused sentence and a comma splice?

A fused sentence has no punctuation between two independent clauses, while a comma splice uses only a comma, which isn't strong enough to separate them.

Can I always use a semicolon to fix a run-on?

Yes, a semicolon is a valid way to join two closely related independent clauses, effectively fixing a run-on sentence.

What are FANBOYS, and how do they help fix run-ons?

FANBOYS (for, and, nor, but, or, yet, so) are coordinating conjunctions. You can use a comma plus a FANBOYS word to correctly join two independent clauses.

Is it ever okay to have a long sentence?

Yes, long sentences are fine if they are grammatically correct and clearly connect ideas. The issue with run-ons is improper joining, not length itself.

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