Comma Before “Because”


Sometimes you need a comma before “because” and sometimes you don’t. This can often be confusing. So here are some guidelines.

Here’s an example:

What do you like about travel? I like travel because it broadens one’s perspective.

This use of “because” does not need a comma after travel.

Most of the time, a comma is used to prevent confusion arising from a sentence having two possible meanings. The Chicago Manual of Style offers the following example and explanation:

He didn’t run, because he was afraid.

He didn’t run because he was afraid.

In the first sentence, because he was afraid isn’t necessary; the main thing is that he didn’t run, and the reason is incidental. [There might be a number of other reasons why he didn’t run (e.g., he didn’t think he could outrun whomever)]

The second sentence, which omits the comma, is unclear. It might mean that he ran, but not because he was afraid. [It might mean that he didn’t run for some other reason than being afraid. For this latter interpretation, some other information would likely be provided or required to explain why he didn’t run (we do know he didn’t run because he was afraid).] To prevent confusion, sometimes you need the comma.

So, how can you figure out when to use a comma and when not to? The answer, though somewhat grammatical sounding, is actually fairly straightforward. It depends on whether the clause that starts with “because” is essential or non-essential.

A clause that starts with because is designed to give a reason or explanation for the main thought of the sentence. It then depends on whether the additional information provided is:

Essential to the main part of the sentence—i.e., the reader needs to know this—in which case, it should not be separated by a comma

Non-essential to the main part of the sentence—i.e., the reader does not need to know this—in which case, it should be separated by a comma.

Other words that are a clue to a clause being essential are: although, because, if, when, where, whether, or who.

Here are two examples:

He was allowed to go to the movies because he had behaved himself.

She can’t go to the movies, because she said she had a previous engagement.

In the first sentence, the words following because are essential to the main thought. The reason is that, with no other information available than He was allowed to go to the movies, readers might wonder why there was ever a question of being allowed or not being allowed. This would make the communication incomplete.

In the second sentence, the writer is stating that She can’t go to the movies, period. That’s the important fact that the writer wants the reader to know. Any explanation is extraneous.


So, when a writer intentionally uses a comma before “because”, or not, he or she is telling readers whether the following information is important to the thought or not, and to eliminate any misunderstanding or confusion. The goal is to recognize when readers might see alternative meanings and be sure to create clear and meaningful sentences.

Copyright © 2016 by Affordable Editing Services

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