Which of the following is correct?
- Are you coming to the gym or not?
- Are you coming to the gym or no?
Which of the following is correct?
- Are you coming to the gym or not?
- Are you coming to the gym or no?
Option 1 is correct, because the sentence is an elliptical construction. Without elision, it would be:
Are you coming to the gym or are you not coming to the gym?
Since "no" obviously doesn't work here, "not" is correct.
Either phrase is redundant. The question, if answered directly, has two alternatives: yes and no. It seems some believe that by actually presenting the two (obvious) alternatives, they will receive a more direct answer. Some will go so far as to add "yes or no?" to the question.
The question, "Are you coming to the gym?" is clear, concise, and calls for one or the other of two alternatives. Of course, it does leave the question open for more clarification as to time, place, etc., but adding "or not" or "or no" adds nothing to that end.
Are you or aren't you coming to the gym?
"Are you coming to the gym or not?" is a bit colloquial, but it is the better one out of the two.