- Generally, there should not be a comma before because in a sentence; this ensures that the cause-and-effect relationship between the dependent clause introduced by because and the main clause remains grammatically clear.
- Occasionally, a comma is necessary before because, especially after a negative statement, to avoid ambiguity about what the because clause refers to.
- You can read a because sentence out loud to check whether a pause before because improves clarity.
- Because introduces a reason, so the phrase “the reason is because …” is redundant and should be avoided.
Because has a straightforward job to do in the English language. It is a subordinating conjunction that indicates a cause-and-effect relationship, introducing dependent clauses that answer the question “Why?”
Most of the time, when the dependent clause that because introduces comes after the independent clause in a sentence, no comma should be used before because. However, exceptions can and should be made when the lack of a comma could lead to misinterpretation.
Here, we’ll explain when to use a comma before because and when to leave it out.
Table of contents
When do you use a comma before because?
Do you ever put a comma after because?
Other tips for using because correctly
How to use because
The word because indicates the cause in a cause-and-effect relationship. It introduces the reason or explanation for something. It can do this in a couple of different ways. One way is as a subordinating conjunction, joining a dependent (or subordinate) clause to an independent clause:
Another way because is used to show the reason for something is alongside of in a prepositional phrase:
As you can see, neither of the above examples has a comma or any other kind of punctuation before because. Although the structures of the two sentences are grammatically different, in each case, the clause or phrase introduced by because is logically essential to the independent clause (“The basketball game ended early”), modifying its verb (ended) by communicating the reason for it, and therefore no comma is used.
Understanding because as a subordinating conjunction
The question of where and how to use commas with because is mostly a question about because as a subordinating conjunction. This is because it is in that usage that because connects clauses, and there are other common kinds of conjunctions (such as coordinating conjunctions) that we very often do see after commas.
When we say because is a subordinating conjunction, we mean that, by definition, it connects a dependent clause to an independent clause, creating a complex sentence. Dependent clauses are logically essential (or restrictive) to the clauses they are dependent on, and the rules of grammatical syntax dictate that when the dependent clause introduced by because follows the independent clause, no comma should precede a subordinating clause between two clauses of this kind:
More specifically, because is a subordinating conjunction that introduces a dependent clause that provides a reason for an effect that is identified in the independent clause that the dependent clause modifies.
In the above example sentence, “I went to the farmers market” is the independent clause; the dependent clause tells us the reason the writer went to the market—they needed ingredients—and the because in the middle signals that the logical relationship between the two clauses is one of cause and effect.
Understanding because of as a two-word preposition
When because is used with of, the two words together form a two-word preposition that forms an adverbial prepositional phrase. In the following example sentence, the prepositional phrase “because of the thunderstorm” modifies the independent clause “The farmers market was closed”:
Why punctuation with because matters
It’s important to put some thought into how you punctuate sentences that use because for clarity: Although it’s normally inappropriate to use a comma before because when because introduces a dependent clause that follows an independent clause, there are times when a comma is necessary to make the meaning of a sentence that uses because unambiguous.
Take a look at this example of a because sentence without a comma:
This sentence can be read in two different ways, and there’s no way for a reader to know which reading the writer intends. The first interpretation is that the writer didn’t go out, and the reason they didn’t go out was that it was raining. The second is that the writer did go out and that they went out for a reason, but that reason was some unspecified one other than the fact that it was raining (i.e., I didn’t go out because it was raining; I went out because I was hungry).
Most likely, it’s the first interpretation that the writer wants to communicate—the reason they avoided going out was the fact that it was raining. They can eliminate the possibility of being misunderstood by adding a comma before because:
In the next sections, we’ll lay out how to recognize and understand the specific circumstances in which it’s necessary to use a comma before because, as well as why it’s usually incorrect and unnecessary to use a comma before because.
When do you use a comma before because?
Most of the time, it is not correct to use a comma before because when because is functioning as a subordinating conjunction that introduces a dependent clause preceded by an independent clause. Following this guideline and leaving the comma out keeps the cause-and-effect logic of your sentence straightforward and clear.
Here are a couple more examples of the kinds of unambiguous sentence structures in which it does not make sense to place a comma before because:
When in doubt, if your sentence makes sense without a comma before because, leave it out.
Next, we’ll dig deeper into the exceptions to the no-comma-before-because guideline. The first two are instances when you should use a comma, and the third is a circumstance in which you can choose to use a comma.
To clarify the meaning of a negative in the independent clause
One situation in which you should use a comma after because as a subordinating conjunction beginning a dependent clause after an independent clause is when the statement of the sentence’s independent clause is negative. In that kind of sentence, a comma eliminates ambiguity. Here’s an example:
This sentence without a comma can be read as meaning two different things, and it’s because the use of the negative can be interpreted two different ways:
- Did Alex not compete in the race because he was registered for the marathon? Perhaps it was a choice he made to conserve his energy for the marathon, for example?
- Or is it that Alex did compete in the race but not because of being registered for the marathon?
In other words, is the writer saying that, although you might assume that Alex competed in the race as training for the marathon he’s registered for next month, he actually competed for some other, unspecified reason?
Let’s assume that the writer’s intended meaning is the first option: Alex did not compete in the race, and the reason is that he was registered for the marathon. The way to clarify that meaning is to add a comma before because:
The grammatical reason that the comma clarifies the sentence is that it makes it clear that the independent clause should be read separately from the dependent clause—the because clause is still dependent on / subordinate to Alex didn’t compete in the race, but it’s nonessential or nonrestrictive to the meaning.
You can probably also hear the difference if you read the sentence aloud without and then with the comma; when you pause after saying “Alex didn’t compete in the race,” it’s clear that that’s a standalone fact, and what follows will be the reason for that fact.
To clarify what sentence element because refers to
The second exception for using a comma before because is when there are multiple elements in the independent clause that because—and the reason it introduces—could refer to, potentially confusing the reader. Look at this example:
Here, the two possible meanings are (1) there may or may not have been a leak in Rachel’s ceiling, but she suspected that there was, and the reason for her suspicion was that her neighbor left the faucet running, and (2) there was a leak in Rachel’s ceiling, and Rachel suspected the cause of the leak was the fact that her neighbor left their faucet running.
The grammatical reason for this sentence’s ambiguity is that the independent clause—“Rachel suspected”—has a dependent clause that is subordinate to it before we even arrive at the because clause: “that there was a leak in her ceiling.”
Since the because clause is the second dependent clause, it could refer to either the independent clause (that’s the first interpretation in the preceding paragraph) or the first dependent clause (second interpretation).
Let’s suppose the first meaning is what we want: Rachel didn’t know for a fact that there was a leak but suspected there was. Adding a comma before because makes it clear that the reason clause is separate from the first dependent clause and thus shouldn’t be read as adding essential information to that clause but as referring back to the main (independent) clause.
If you read the sentence aloud with the comma, you’ll probably be able to hear the difference in clarity that the comma makes:
To indicate a pause or emphasize contrast
You can use a comma before because for emphasis when the reason introduced by because needs extra attention or a slight pause, as in the following sentence:
Keep in mind that this usage is a stylistic choice and should be used sparingly, and probably not in formal contexts. When in doubt, read the sentence aloud to yourself to check whether a pause before because improves clarity.
Do you ever put a comma after because?
There’s no grammatical reason specific to the word because that calls for a comma after it. But if a because clause is interrupted by a nonessential clause or phrase, that nonessential clause should be set off by commas (or dashes or parentheses) as usual:
Other tips for using because correctly
Besides the comma question, there are a handful of other things it’s helpful to keep in mind about because.
Dependent clauses before independent clauses
When a dependent clause such as a because clause appears before the independent clause in a sentence, the dependent clause is followed by a comma:
Since vs. because
The conjunction since is often used in contemporary English as a synonym for because. This is now widely accepted in most contexts but should be avoided in more formal ones, or if any misunderstanding is possible due to the fact that since can express time (I haven’t been back there since January) as well as causation (Since we have already covered this material, let’s just do a quick catchup).
Avoid the reason is because
Because means for the reason that. This makes the phrase the reason is because—though common in conversational English—redundant and best avoided in writing:
Most of the time, there should not be a comma before the subordinating conjunction because. When a comma is necessary or useful for clarity or emphasis, you can often hear the difference a pause makes when you read the sentence aloud, and now you’ll have the grammatical understanding to back that up.
Comma before because FAQs
Should there be a comma before because?
Generally, there should not be a comma before because so that the causal relationship between the dependent clause introduced by because and the independent clause remains grammatically clear.
Are there exceptions to the general rule against using a comma before because?
You should use a comma before because to clarify what a negative in the independent clause refers to or whether because refers to the independent clause or another dependent clause. You can also occasionally place a discretionary comma before because if a pause there creates the emphasis you want.
Should there be a comma after because?
The only time there should be a comma after because is to set off a parenthetical or otherwise nonessential element in the sentence that is interrupting the because clause.
