For example, in the expression "I don't know whether I'm coming or going", would saying if in place of whether be a big mistake? Would doing it in written English be an error too?

5 Answers 5


In general, if and whether can be substituted for each other. In certain situations, they have different meanings. For example:

I don't know whether I should arrive on Friday or Saturday

I don't know if I should arrive on Friday or Saturday

The first sentence implies that the person will arrive, but they are not sure when. The second sentence could be read that the person might not arrive at all.

  • 1
    The example is a common expression meaning basically "I'm confused." More explanation here. Commented Jan 29, 2013 at 19:38

Formally, if should be used when you have a conditional sentence and where whether should be used when you are showing that two alternatives are possible.

In the sentence asked, both are correct.


In the questioned sentence, "if" can be used to imply that the person saying it may not be either coming or going, but could be standing still, or even running around in circles.

"Whether" implies that "coming" and "going" are the only possibilities.


If could be used in place of whether.

They would have the same effect, and the same meaning.

So no, it wouldn't be a big mistake.


I find that if is commonly substituted for whether in informal English (the reverse does not happen). This is one of my personal bugbears: I try to get it "right", but in practise most people are happy to let it slide.


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