Free Run on Sentence Checker!

SentenceCheckup eliminates sentence structure issues, run on sentences, and sentence fragments. Make your writing error-free today!

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Free Sentence Checker

Check and correct run on sentences in your blog posts, academic papers, and essays.

Tired of grappling with those never-ending sentences that wreck your writing flow and leave your readers confused? We get it. Sentence Checkup’s sentence checker will help you make complex sentences clearer and easy to read.

Completely free to use

Quickly checks and corrects sentences

Advanced AI Technology for enhanced accuracy

Make your sentences easy to read

Access it from any device

What is a Run on Sentence?

A run on sentence combines two or more independent clauses in one sentence without proper punctuation or conjunctions. It thus results in sentences that are too long and often confusing and hard to read. Think of them as sentences that are cramming multiple thoughts or ideas together without giving the reader a clear break.

How can sentence checker help?

The Sentence Checkup’s sentence checker is like having a skilled editor by your side. Our sentence checker improves your writing by making those cumbersome sentences more accurate, clear, and readable.

Simply copy and paste the text, and the tool will identify and correct run on sentences, fargments and structure issues.

Refine and Fix Your Sentence

Corrects Comma Splices

The checker identifies and fixes comma splices. Change “He loves cooking, he often experiments with new recipes” to the grammatically correct “He loves cooking; he often experiments with new recipes.” No more pesky comma splices!

Detects and Corrects Punctuation

The punctuation checker suggests where to add necessary punctuation marks like commas, semicolons, or periods.

Adds Conjunctions 

It may recommend adding conjunctions (like ‘and’, ‘but’, ‘although’, etc) to connect clauses properly. For example, in “I was tired I still finished the project,” the tool might suggest “I was tired, but I still finished the project.”

Splitting Sentences

The tool suggests splitting a run on sentence into two or more separate sentences. From “She enjoys painting her artwork is quite impressive,” it would make two sentences: “She enjoys painting. Her artwork is quite impressive.”

Write with More Confidence

Don’t just take our word for it. Over 20,000 students, writers, and professionals like you have improved their writing with our Run On Sentence Checker.

Don’t let long sentences slow you down. 

How Sentence Checkup’s Sentence Checker Works

This sentence checking tool uses advanced AI to check for punctuation, grammar, and spelling errors and improve your sentences. You can check sentence structure issues in just three steps:

Step One

Copy and paste the text you want to check into our tool.

Step Two

Click the “Check” button, and it will highlight all mistakes.

Step Three

You can correct them one by one by hovering over to the highlighted text, or hit the “Correct” button to correct all errors in just one click.


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