Paste a sentence or short paragraph and check whether it contains a run-on sentence, comma splice, fused sentence, or fragment. The tool helps you split ideas, add punctuation, choose conjunctions, and keep the original meaning clear.
Input
I wanted to go for a walk, it started raining before lunch.
Suggested Fix
I wanted to go for a walk, but it started raining before lunch.
Other Fixes
1. I wanted to go for a walk. It started raining before lunch.
2. Because it started raining before lunch, I could not go for a walk.
A run-on sentence is not just a long sentence. It usually joins complete thoughts without the right punctuation or connector.
Input
The meeting ran late, everyone missed the train.
Cleaner version
The meeting ran late, so everyone missed the train.
The checker can replace the comma splice with a coordinating conjunction, a period, or a semicolon.
Input
The student finished the draft she forgot to check the citations.
Cleaner version
The student finished the draft, but she forgot to check the citations.
A fused sentence needs a boundary between complete ideas so readers can follow the relationship.
Input
Because the paragraph had no main verb.
Cleaner version
Because the paragraph had no main verb, the teacher marked it as a fragment.
The tool also checks nearby fragment patterns because they often appear in the same editing workflow.
Use the tool as a fast editing pass before submitting an essay, email, report, or classroom exercise.
Enter the sentence you are unsure about. The checker works best when you include the whole sentence, not only the phrase that looks wrong.
The tool looks for independent clauses, missing punctuation, comma splices, fused sentences, fragments, and connectors that do not match the meaning.
Review the suggested repair. Sometimes splitting into two sentences is clearest; sometimes a semicolon, coordinating conjunction, or subordinating conjunction keeps the ideas connected.
The best repair depends on how the ideas are related. Do not simply add a comma unless the grammar supports it.
| Problem | Best fix | Example |
|---|---|---|
| Two equal ideas | Split into two sentences or use a semicolon. | The draft was finished. The citations still needed checking. |
| Cause or result | Use so, because, since, or therefore when the relationship is clear. | The meeting ran late, so everyone missed the train. |
| Contrast | Use but, although, while, or however with correct punctuation. | The student finished the draft, but she forgot the citations. |
| Check | Why it matters | Action |
|---|---|---|
| Independent clauses | A run-on usually contains two complete thoughts that need a clearer boundary. | Add a period, semicolon, or comma plus conjunction. |
| Comma splices | A comma alone cannot join two complete sentences in formal writing. | Replace the comma with a stronger punctuation or connector. |
| Fragments | Some sentences feel wrong because they are incomplete, not because they are too long. | Add a main clause or attach the fragment to a complete sentence. |
Grammar checking should improve clarity without erasing your voice or changing the facts.
A sentence can be long and still correct if its clauses are connected properly. The checker focuses on structure, not length alone.
Creative writing may use fragments or long rhythms on purpose. For school, business, and academic work, choose the grammatically complete repair.
Avoid pasting private student records, confidential work, passwords, medical details, or legal documents into any online writing tool.
A run-on sentence checker looks for complete thoughts that are joined without correct punctuation or connectors. It can suggest splitting the sentence, adding a semicolon, or using a conjunction.
A comma splice is a common type of run-on sentence. It happens when two independent clauses are joined with only a comma.
You can fix it by making two sentences, using a semicolon, adding a comma plus a coordinating conjunction, or making one clause dependent with words such as because, although, or when.
Yes. It can flag likely fragments as well as run-ons, then suggest a full sentence that has a clear subject, verb, and main idea.
No. Length alone does not create a run-on. A long sentence can be correct when its clauses are connected with proper punctuation and grammar.