Comma Before Because | Correct Use & Examples

There should be no comma before “because” when it’s used to introduce a reason that is essential to the meaning of the sentence.

For example, the point of the sentence below is to explain why the project failed.

Example: Because introducing essential information
The project failed because the team lacked proper communication.

When a comma is added before “because,” the reason is no longer emphasized. Instead, the sentence focuses on the fact the project failed; the reason it failed is less important.

Example: Comma before because
The project failed, because the team lacked proper communication.

When to use a comma before because (positive statements)

A positive statement is one that does not include the adverb “not.” When a comma is added before “because” in a positive statement, it places an emphasis on the independent clause. When a comma is not included, emphasis is placed on the “because” clause.

The context is important when choosing whether to include a comma. Consider the example below.

Example: Because introducing essential information
Emma was late because she overslept. I was late because of traffic. There’s a big difference!

The main point of these sentences is to distinguish between the subjects’ reasons for being late. In both sentences, “because” is used to introduce information that is essential to the meaning. Therefore, the “because” clauses should not be preceded by commas.

Consider another example that contains a comma.

Example: Because introducing nonessential information
Emma was late, because she overslept, but she will make up for it by working this weekend.

The point of this sentence is that, although Emma was late, she will make up for the time she missed. Her reason for being late is included, but it is not essential to the sentence’s meaning. It could be removed, set off by em dashes, or enclosed in parentheses without impacting the meaning of the sentence.

Example: Nonessential because clause
Emma was late (because she overslept), but she will make up for it by working this weekend.

Emma was late—because she overslept—but she will make up for it by working this weekend.

Emma was late, but she will make up for it by working this weekend.

When to use a comma before because (negative statements)

A negative statement is one that includes “not” or a contraction like “didn’t” or “can’t.”
When “because” is used in a negative statement, it is sometimes unclear whether it expresses:

  • A correct reason that something did not occur, or
  • An incorrect reason for something that did occur

Correct reason

You need a comma before “because” when the clause it introduces correctly explains why something did not occur. This indicates that the “because” clause provides the reason for the negative statement.

Example: Comma before because in a negative statement
The artist isn’t popular, because he’s eccentric.

In the example above, it’s clear that the artist is not popular and that the reason for this is his eccentricity.

Because the comma is included, the meaning of the sentence is already clear, so there’s no need to rephrase the sentence or include additional information.

Incorrect reason

Don’t put a comma before “because” when the clause it introduces incorrectly explains why something did occur.

Example: Because introducing an incorrect reason
The artist isn’t popular because he’s eccentric. He’s popular because his work is raw and powerful.

In the example above, it’s evident that the artist is indeed popular, but it’s not because he’s eccentric.

However, when the first sentence appears by itself, it’s unclear whether the “because” clause or the “the artist is popular” clause is being negated. In instances like this, it’s best to either rephrase the sentence or provide additional context:

Example: Ambiguous because clause
  • The artist isn’t popular because he’s eccentric.
  • It’s not because of his eccentricity that the artist is popular.

When do you put a comma after because?

In most cases, it’s incorrect to add a comma after “because.”

Example: Incorrect comma after because
  • That’s because, the flight took longer than expected.

A comma should only appear after “because” when it is followed by an interrupter (i.e., a parenthetical expression that is used to qualify a statement or add emphasis). A comma should also appear after the interrupter.

Example: Comma after because
The party was canceled because, unfortunately, the host was ill.

Alana didn’t sleep last night because, as you can imagine, she was excited.

Because clause at the start of a sentence

As a subordinating conjunction, “because” is used to introduce a subordinate clause (or dependent clause) that does not express a complete thought and must be connected to an independent clause that comes before or after it.

When the “because” clause appears at the start of a sentence, it should always be followed by a comma that separates it from the independent clause.

Example: Because clause at the start of a sentence
Because it was the weekend, we slept in.

It is grammatically incorrect to use a “because” clause on its own. When used in this way, it is a sentence fragment.

While sentence fragments are acceptable in informal contexts, they should be avoided in professional communication and academic writing. Instead, connect the “because” clause to an independent clause that comes before or after it.

Example: Sentence fragment
  • The trend is expected to continue. Because of ongoing technological advances.
  • Because of ongoing technological advances, the trend is expected to continue.

Frequently asked questions about using commas before because

Is “because” a conjunctive adverb?

“Because” isn’t a conjunctive adverb; it’s a subordinating conjunction. Subordinating conjunctions connect subordinate clauses (aka dependent clauses) to independent clauses in a single sentence. For example, “I went to the beach because it was sunny.”

Conjunctive adverbs (e.g., “however,” “moreover”) are adverbs that act in a similar way to conjunctions, linking the ideas in two sentences or statements together. They can link independent clauses with the help of additional punctuation. For example, “it was sunny; therefore, I went to the beach.”

Is “because” a coordinating conjunction?

No, “because” is not a coordinating conjunction. Instead, it is classified as a subordinating conjunction when used in sentences like this: “I bought this phone because it has a good battery.”

In this sentence, “because” is connecting an independent clause with a dependent clause.

Is “because” a subordinating conjunction?

Yes, because is a subordinating conjunction. It is used to introduce a dependent clause that gives a reason for/cause of something (e.g., “The picnic is canceled because rain is forecast”).

Note that the phrase because of is not a subordinating conjunction. It functions as a preposition meaning “on account of” (e.g., “The picnic is canceled because of the rain”).

The QuillBot Grammar Checker can help ensure you’re using subordinating conjunctions and prepositions correctly.

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Eoghan Ryan, MA

Eoghan has taught university English courses on effective research and writing. He is particularly interested in language, poetry, and storytelling.