The Core Rule
Comma splice = two independent clauses joined by only a comma.Source-1✅
❌ Wrong
I was tired, I went home.
✅ Correct
I was tired. I went home.
✅ Correct
I was tired, so I went home.
Key idea: A comma can be part of the solution, but it usually needs backup (a conjunction, a semicolon, or a new sentence).
A comma splice is a sentence-boundary problem. It looks small on the page, but it changes how readers hear your meaning.
- Punctuation
- Sentence Boundaries
- Independent Clauses
- Common Writing Error
Table of Contents
Comma Splice Meaning and Basic Pattern
That simple pattern is why the comma splice shows up so often. The comma feels like a pause, but it is not a full sentence break.
Independent Clause Check
You can’t spot a comma splice until you know whether each side is an independent clause. A classic independent clause can stand alone as a sentence.Source-3✅
- Find the subjects: do both sides have their own subject?
- Find the verbs: does each side have a main verb that completes a thought?
- Read each side aloud: can each side stand alone as a complete sentence?
Small but important: If the second part is missing its own subject (for example, it’s sharing the first one), it may not be an independent clause. That means it’s not automatically a comma splice.
Why This Mistake Happens
Most comma splices happen for one basic reason: we write commas the way we speak. In speech, a pause can feel “strong enough,” but on the page you need a real join or a real break.
Another common trigger: mixing up FANBOYS (coordinating conjunctions) with words like however and therefore. Those are not FANBOYS, and they take different punctuation.Source-4✅
- FANBOYS can link two independent clauses with a comma.
- Conjunctive adverbs usually need a period or semicolon before them when they sit between two complete sentences.
Reliable Fix Options
Once you’ve confirmed “two full sentences,” the fix is not mysterious. Most writing handouts describe the same core set of repairs: separate the sentences, use a semicolon, use a coordinating conjunction, or turn one side into a dependent clause.Source-5✅
| Option | What Changes | What It Signals | Example |
|---|---|---|---|
| ✅ Period | Comma becomes a full stop. | Two clean sentences; the link is understood by context. | The store was closed. I came back later. |
| ✅ Semicolon | Comma becomes a semicolon. | Two sentences are closely related. | The store was closed; I came back later. |
| ✅ Comma + FANBOYS | Add a coordinating conjunction. | The conjunction names the relationship (contrast, result, choice). | The store was closed, so I came back later. |
| ✅ Subordination | One clause becomes dependent. | One idea becomes supporting background for the other. | Because the store was closed, I came back later. |
Meaning stays the same, but the feel changes. A period feels crisp. A semicolon feels tighter. A conjunction feels explicit.
Conjunctive Adverbs and Semicolons
Words like however, therefore, and moreover often sit between two complete sentences. In that spot, common guidance is: semicolon before, comma after the conjunctive adverb.Source-6✅
Side-by-side: the same idea, with different sentence boundaries.
- ❌ Comma splice The bus was late, however I still arrived on time.
- ✅ Semicolon pattern The bus was late; however, I still arrived on time.
- ✅ Period pattern The bus was late. However, I still arrived on time.
Examples and Near-Misses
A good comma splice example has two parts that are each a full sentence. A near-miss looks similar, but one side is not an independent clause. Many guides discuss these alongside other boundary errors like fused sentences and run-ons.Source-2✅
Clear Comma Splice
❌ Wrong Ava finished early, she left quietly.
✅ Correct Ava finished early. She left quietly.
✅ Correct Ava finished early, so she left quietly.
Near-Miss (Not two full sentences)
✅ Not a splice Ava finished early and left quietly.
Why: the second part doesn’t have its own subject, so it’s not a separate independent clause.
Common “looks-like-a-splice” patterns that usually are something else:
- Shared subject: Leo grabbed his keys and ran.
- Dependent clause: Because it rained, we stayed inside.
- Appositive or extra info: The package, a small box, arrived today.
FAQ
Frequently Asked Questions
Is a comma splice the same as a run-on sentence?
A comma splice is one kind of sentence-boundary error. Many resources group it with other run-on problems, especially fused sentences (no punctuation at all).
Is it ever correct to join two independent clauses with a comma?
Yes, when the comma is paired with a coordinating conjunction (FANBOYS). The comma alone is the issue, not the comma-plus-conjunction pattern.
What is the simplest edit that removes a comma splice?
Changing the comma to a period cleanly separates the two sentences. It’s the most straightforward boundary fix.
Does adding “however” after a comma fix a comma splice?
No. However is a conjunctive adverb, not a FANBOYS conjunction. It typically needs a period or semicolon before it when it sits between two complete sentences.
Can a comma splice happen with very short clauses?
Absolutely. Length doesn’t matter. If both sides are independent clauses and the only join is a comma, it’s still a comma splice.
If the second part has no subject, is it a comma splice?
Usually not. A true comma splice needs two independent clauses. If the second part is missing its own subject, it often isn’t an independent clause at all.