The difference between using “whether or not” versus just “whether” is the result of the outcome in any given situation. “Whether or not” suggests a result that’s the same, no matter how something turns out. “Whether” indicates an undetermined outcome.
However, traditionally speaking, “whether or not” is the more correct one to use. Many modern linguists suggest “or not” is superfluous and extraneous, inferring it’s unnecessary. This is not true and presents a disservice to the English language. Saying such things encourages intellectual laziness.
“Whether or Not”
“Whether or not” is a conjunction phrase that expresses a choice between alternatives that don’t matter regardless of how the event or situation ends. This means there should be more than one option given in a list.
You can choose which ingredients you like whether they are gluten and phthalate-free or not.
Whether or not it’s raining or sunny, we’re training outside.
I don’t care whether you want to come or not, I have to go back to the library.
As a sole conjunction, “whether” serves as a means for expressing doubt or uncertainty about the outcome of any given event, situation, or circumstance. While you can use it alone, it’s become optional to do this. Traditionally, it is wrong to omit the “or not” part, even if it doesn’t contain a varied list of choices.
He’s coming along for the road trip whether we complain.
Whether you live here or over there, it doesn’t matter to me.
I will not comply whether there are military forces.
Because both “whether or not” or “whether” suggest “regardless,” you can use “regardless if” or “if” to check and ensure you’re using either one correctly.
You can choose which ingredients you like regardless if they are gluten and phthalate-free.
If it’s raining or sunny, we’re training outside.
I don’t care if you want to come, I have to go back to the library.
He’s coming along for the road trip regardless if we complain.
Regardless if you live here or over there, it doesn’t matter to me.
I will not comply if there are military forces.
So, if you want to remove the “or not” in conjunction with “whether,” then use “regardless if” or just “if.” It will show a command and respect for the English language with a refined nuance.