Run-on sentences and comma splices are two common sentence structure mistakes that can make writing confusing. While they may seem similar, they are different errors:
- A run-on sentence occurs when two or more independent clauses (complete sentences) are joined incorrectly without proper punctuation or a conjunction.
- A comma splice happens when two independent clauses are incorrectly joined by only a comma.
Let’s look at examples of both errors and how to fix them.
Run-on Sentences
A run-on sentence happens when two complete thoughts are put together without punctuation or a conjunction.
🔴 Incorrect:
👉 She loves to read she spends hours at the library.
(Two independent clauses are joined with no punctuation.)
✅ Ways to Fix It:
- Use a period:
She loves to read. She spends hours at the library. - Use a semicolon:
She loves to read; she spends hours at the library. - Use a comma + coordinating conjunction:
She loves to read, so she spends hours at the library.
Comma Splices
A comma splice occurs when two independent clauses are joined only by a comma, which is not strong enough to connect them.
🔴 Incorrect:
👉 It started to rain, we ran inside.
(A comma alone cannot join these two complete sentences.)
✅ Ways to Fix It:
- Use a period:
It started to rain. We ran inside. - Use a semicolon:
It started to rain; we ran inside. - Use a comma + coordinating conjunction:
It started to rain, so we ran inside. - Use a subordinating conjunction:
When it started to rain, we ran inside.
Proper punctuation and conjunctions help keep your writing clear, avoiding run-ons and comma splices.
