Independent Clauses
Learn what makes an independent clause complete, how two of them can be joined correctly, and the mistakes that happen when they are joined incorrectly.
Standing alone
An independent clause is a complete sentence on its own.
An independent clause contains a subject and a verb, and it expresses a complete thought. Because it is complete on its own, it can stand alone as its own sentence.
In the sentence She left early., the subject she and the verb left together express a complete idea. Nothing further is needed for the sentence to make sense.
Independent clauses can also be joined to one another, or to a dependent clause, to build longer sentences.
Before you begin
Independent clauses are one of five clause types.
This lesson focuses on independent clauses specifically. Clauses as a whole include four other types, each covered in its own lesson.
If you would like an overview of how clauses work in general, begin with the Clauses page.
The central idea
A complete thought needs both a subject and a verb.
Compare a complete independent clause with a group of words missing one of those parts.
01
Independent Clause
She left early.
02
Incomplete
Left early.
The useful question is: does this group of words have both a subject and a verb?
Left early has a verb, left, but no subject. Without a subject, the group of words does not express a complete thought and cannot stand alone as a sentence.
What every independent clause needs
Three elements make a clause independent.
A subject
The train arrived on time.
The person or thing the clause is about.
A verb
The train arrived on time.
The action or state the subject is connected to.
A complete thought
The subject and verb together must express an idea that does not depend on anything else to make sense.
Joining two independent clauses
Three correct ways exist to combine them.
A comma and a coordinating conjunction
The rain stopped, but the sky stayed grey.
A semicolon
The rain stopped; the sky stayed grey.
A semicolon joins two closely related independent clauses without a conjunction.
A period, as two separate sentences
The rain stopped. The sky stayed grey.
Two ways joining goes wrong
A comma alone, or no punctuation at all, is not enough.
The comma splice
The rain stopped, the sky stayed grey.
A comma alone cannot join two independent clauses; this is known as a comma splice.
The run-on sentence
The rain stopped the sky stayed grey.
With no punctuation at all between them, two independent clauses run together and become difficult to read.
A useful decision guide
Ask whether the clause is complete, and how it connects to others.
01
Does the group of words have a subject and a verb?
Both are needed before it can be independent.
02
Does it express a complete thought on its own?
If it needs something else to make sense, it is not independent.
03
Is it being joined to another independent clause?
Use a comma with a conjunction, a semicolon, or a period.
04
Is a comma being used on its own between two independent clauses?
That combination is a comma splice, and needs a conjunction or a different punctuation mark.
Common mistakes
An independent clause needs to be both complete and correctly joined.
A fragment is missing a subject or a verb.
Not: Because it was raining.
Correct: Because it was raining, they stayed inside.
Even though this group of words has a subject and a verb, because makes it dependent, not a complete thought on its own.
A comma alone cannot join two independent clauses.
Not: She finished the report, she went home.
Correct: She finished the report, and she went home.
No punctuation at all creates a run-on sentence.
Not: She finished the report she went home.
Correct: She finished the report. She went home.
Check your understanding
Is each group of words an independent clause?
Choose the correct answer for each example.
The museum closes at six.
✅ Exactly! It has a subject, a verb, and expresses a complete thought.
❎ Not quite. Check whether it has both a subject and a verb, and makes sense on its own.
Does this make sense as a stand-alone sentence?
Although the museum closes at six
✅ Exactly! Although makes this clause depend on another one to be complete.
❎ Not quite. This group of words has a subject and a verb, but does it make complete sense alone?
What does the word “although” do to a clause?
Closes at six today.
✅ Exactly! There is no subject stated, so this is a fragment.
❎ Not quite. Look for a subject: who or what closes at six?
Who or what is doing the closing?
Choose the best explanation
Select the sentence that explains the mistake correctly.
Why is “She finished the report, she went home.” not correctly punctuated?
✅ Exactly! This is a comma splice; a conjunction, a semicolon, or a period is needed.
❎ Not quite. Check whether both halves of the sentence could stand alone.
Why is “Because it was raining.” not a complete sentence on its own?
✅ Exactly! The clause has a subject and a verb, but “because” leaves it needing an independent clause to attach to.
❎ Not quite. Look closely for the subject, “it”, and the verb, “was raining”.
Try it another way
Fix each comma splice.
Rewrite the sentence using a correct way of joining the clauses.
The lights went out, we lit some candles.
✅ Exactly! Adding a coordinating conjunction after the comma fixes the splice.
❎ Not quite. Add a conjunction after the comma, or use a semicolon or a period instead.
The store was closed, we went home.
✅ Exactly! A semicolon correctly joins these two closely related independent clauses.
❎ Not quite. Try a semicolon, a conjunction, or splitting this into two sentences.
Quick review
A subject, a verb, and a complete thought make a clause independent.
An independent clause contains a subject and a verb, and expresses a complete thought on its own.
Two independent clauses can be joined with a comma and a coordinating conjunction, a semicolon, or split into separate sentences with a period.
A comma splice uses a comma alone to join two independent clauses, which is not correct in standard English.
A run-on sentence joins two independent clauses with no punctuation at all.
Remember
Check for a subject, a verb, and a thought that stands on its own.
If all three are present, the clause is independent. If it is being joined to another independent clause, choose a conjunction with a comma, a semicolon, or a period.