Comma Checker
Fix Missing and Misplaced Commas
Paste your text to catch missing commas, comma splices, and list punctuation errors. The grammar checker fixes commas alongside other improvements in one pass.
Comma splice, semicolon, or a new sentence? Three ways to fix it
A comma splice is two complete sentences joined by a comma alone. All three fixes below are correct — the right one depends on how closely the two clauses relate and how long they are. The checker fixes a comma splice for you but never says which option it picked — this table is here so you can decide by hand.
Add a coordinating conjunction
Two short, closely related independent clauses
The report is due Friday, so we need to start reviewing it now.Use a semicolon
You want to keep the link without naming the relationship a conjunction would state.
The report is due Friday; we need to start reviewing it now.Split into two sentences
The clauses are long, or only loosely related
The report is due Friday. We need to start reviewing it now.
Comma Errors
Commas are the most misused punctuation mark — and the hardest to get right
Missing commas change meaning: 'Let's eat grandma' vs 'Let's eat, grandma.' Comma splices create run-on sentences. Serial commas prevent ambiguity in lists. The checker catches all three patterns as part of a full grammar pass.
Comma errors are the most common punctuation mistakes in English writing. Paste your text above to get an AI-powered grammar check that catches comma issues alongside spelling, syntax, and other errors in a single pass.
- Missing commas after introductory phrases ("However we decided...")
- Comma splices — two sentences joined by a comma alone
- Missing serial commas in lists of three or more items
The checker corrects commas as part of a full grammar improvement. It does not isolate comma-only errors — you get a complete corrected text.
See the difference
Comma errors in, clean punctuation out — with corrections highlighted.
How to check commas in your text
Paste your text — email, essay, or any writing where commas matter.
The grammar checker fixes comma errors alongside spelling and syntax improvements.
Copy the corrected text or open the full grammar tool for a detailed review.
This tool handles
- Missing commas after introductory clauses (After the meeting, …)
- Comma splices — two independent clauses joined only by a comma
- Missing serial / Oxford commas in lists of three or more items
- Commas with coordinating conjunctions (and, but, or) joining clauses
- Restrictive vs non-restrictive clause commas (the writer who… vs the writer, who…)
- Misplaced commas inside compound predicates that change meaning
Not in scope
- Style debates (whether to enforce Oxford commas in every list)
- Comma-only output — fixes always travel with full grammar pass
- Style guide enforcement (AP vs Chicago vs MLA differences)
- Languages other than English for comma-specific rules — comma conventions differ across languages
Try the checker above on a real paragraph. The deep-dive below covers each comma category, when to break the rules, and which sentences a checker can’t safely fix on its own.
Frequently asked questions
Does it only check commas?
No. The grammar checker corrects comma errors as part of a full grammar, spelling, and syntax check. This page focuses on comma-specific guidance, but the tool improves your entire text.
What comma errors does it catch?
Missing commas after introductory clauses, comma splices (two independent clauses joined by a comma), missing serial/Oxford commas in lists, and commas that change sentence meaning.
Does it add Oxford commas?
The tool follows standard punctuation conventions. It adds commas where they are clearly needed for readability or correctness, but does not enforce a strict Oxford comma preference in ambiguous cases.
When should I use a comma vs a semicolon?
Use a comma with a coordinating conjunction (and, but, or) to join independent clauses. Use a semicolon when you want to keep the link without naming the relationship a conjunction would state. A comma alone between independent clauses is a comma splice — the checker catches these.
Can it fix commas in long, complex sentences?
Yes. The AI-powered checker handles compound and complex sentences, including nested clauses. For very long sentences, consider splitting them — the checker will suggest improvements even if commas are technically correct.
Need a full grammar check?
The Grammar Checker catches spelling, syntax, and punctuation in one pass