I have seen 'since', 'because', 'as', 'due to', and 'for the purpose of' in different text and I was wondering what is the difference between them.

Looking into Longman dictionary, I found very similar definitions for the 5 of them. Here are the definitions:


Used to give the reason for something:

E.g., Since you are unable to answer, perhaps we should ask someone else.


Used when you are giving the reason for something:

E.g. 1, We didn't enjoy the day because the weather was so awful.

E.g. 2, Because you're not old enough.

E.g. 3, Hubert never experienced any fear, and this was partly because he was not particularly intelligent.

E.g. 4, Many exam candidates lose marks simply because they do not read the questions properly.

E.g. 5, I decided to go with them, mainly because I had nothing better to do.


used to state why a particular situation exists or why someone does something:

E.g. 1, As it was getting late, I turned around to start for home.

E.g. 2, We asked Philip to come with us, as he knew the road.

due to:

because of something:

E.g. 1, The court of inquiry ruled that the crash was due to pilot error.

E.g. 2, She has been absent from work due to illness.

E.g. 3, The restaurant's success was due largely to its new manager.

E.g. 4, Attendance at the meeting was small, due in part to (=partly because of) the absence of teachers.

for/with the purpose of doing something:

E.g. 1, Troops were sent solely for the purpose of assisting refugees.

E.g. 2, He came here with the purpose of carrying out the attack.

closed as too broad by Nathan Tuggy, user3169, Ben Kovitz, ColleenV, user24743 May 27 '16 at 1:23

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.


They can have similar or different meanings, depending on the context.. Let's look at some examples.


It's been a long time since I ate sushi.

Here, 'since' is used to express that a long time has passed from the time you last ate sushi.

I can't see, since I don't have my glasses on.

Here, 'since' is similar to the word 'because'. It's used to indicate the reason for not being able to see. These two different usages of "since" are completely different.


"I don't understand what you are saying, because English is not my native language"

Again, like our second usage of "since", "because" is expressing the reason for something happening, or the 'cause' of something happening, i.e., "Smoking is the cause for most lung problems"


"As" could have different meanings also, depending on context. Here are a few examples.

He had glasses on, as he wouldn't be able to see without them.

Here, "as" has the same meaning of "because", but this is used less in normal conversation. Most people would prefer to use "since" or "because" in this case.

Thomas, or Tommy, as he liked to be called, was late for the meeting.

Here, "as" is used to indicate that Thomas would prefer to be called Tommy. "as" is comparing his real name to his nickname. In a general since, "as" is used to compare things.

She was beautiful, as a rose.

Due to

This is generally a more formal expression of cause. People do use it in conversation, but you are more likely to see it in writing than you are to hear it.

The explosion at the factory was due to a lack of safety procedures.

The real interest here could be in the adjective "due". When something is due, it indicates that it is expected to to be given to someone or something else.

I have money, but $500 of it is due to my landlord for rent.

In the same way, the responsibility for the explosion in the factory "belongs" to the lack of safety procedures.

For the purpose of

This is also expressing a cause, but indicates that there is a specific action associated with the cause.

I baked a delicious cake, for the purpose of impressing my wife.

In this case we are saying the one and only reason I made the cake was to impress my wife. I didn't make the cake for me, or anybody else. I made it because I wanted her to be impressed.

Here is how the sentence would look if we used the word "because"

I baked a delicious cake, because I wanted to impress my wife.

  • Thank you so much for your comprehensive answer. Do you know what's wrong with my question that people gave it negative points? – user2521204 May 26 '16 at 22:03
  • @user2521204 If you check out help center, especially the "how to ask" section, you will get some advice on writing questions that may get a better response. I think it is because you didn't show in your question that you tried to find an answer before you asked. If you explained why looking in a dictionary didn't help you, that would be one step toward making your question better. – ColleenV May 26 '16 at 22:29
  • @ColleenV, would you please take a look at my question now and let me know if it is better? – user2521204 May 26 '16 at 23:21

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