Grammar: "because" and comma usage

Should you use a comma when you use the word because?

I see that people are often unsure whether they should use a comma (,) before the word "because" or not. This post is here to clear up any confusion.

So, when to use a comma before the word "because"?

Below are two sentences that are exactly the same except for the comma before the word "because". What is the difference in meaning between them?

1. I know the reason he committed suicide because his wife phoned me. 
2. I know the reason he committed suicide, because his wife phoned me. 

Which sentence communicates that the reason for the suicide was the phone call? Reveal Answer The first sentence

Which sentence communicates that I learned about the suicide from the phone call? Reveal Answer The second sentence

That's a huge difference in meaning!

Let's discover what this means for our comma usage and the word "because". Use the example sentence to complete the rules below. 

So, we DO NOT use a comma when choose the because statement immediately links to what preceded it the because statement modifies the entire sentence that preceded it

So, we DO use a comma when  choose the because statement immediately links to what preceded it the because statement modifies the entire sentence

???????

Let's practice. What's the difference in meaning between these sentences?

• He didn't run, because he was afraid. 
• Why didn't he run?
• Reveal Answer Because he was afraid.
• He didn't run because he was afraid. 
• Why didn't he run?
• Reveal Answer NOT because he was afraid, but something else.

• They didn't want her on the committee because she was so outspoken. 
• What was the reason they didn't want her on the committee?
• Reveal Answer NOT because she was outspoken, but something else.

• They didn't want her on the committee, because she was so outspoken. 
• What was the reason they didn't want her on the committee?
• Reveal Answer Because she was so outspoken.

Basically, if you add a comma, the "because" statement refers to the entire preceding sentence. If you don't add a comma, the "because statement" only refers to the words directly before it. This can have a profound impact on meaning!

Final Remarks

Remember this rule and you'll know exactly when to use a comma and when not to use a comma before the word "because". And as we can see here, that comma can drastically change the meaning of the sentence, so be accurate!