English can be quite confusing and tricky. Sometimes, people fail to understand the difference between two similar-looking words and avoid using them completely. Such a case can be seen with the words whether and whether or not.
In most cases, the additional phrase or not with whether may seem very redundant and unnecessary. And in fact, it is possible that it can be removed and only whether can be applied. However, that cannot be the case always.
Whether is usually used when there is a possibility of two alternatives, which means it implies a binary choice. And sometimes, whether or not can be reduced to only whether when the sentence shows two alternatives.
- I don’t know whether I can come tomorrow.
- I don’t know whether or not I can come tomorrow.
However, in some cases, whether or not is essential and different. Whether or not means regardless of whether. That means, regardless of any circumstances, an output is possible. Thus, whether or not is necessary when we show that despite any given situation, the response would be the same.
- I will attend the meeting whether or not I am prepared.
- I am leaving school, whether or not you are mad.
Here, we cannot write I am leaving school whether you are mad or I will attend the meeting whether I am prepared. It will stand incorrect.
This is the difference between the two. While whether or not might seem unnecessary, it is essential in some particular cases.