We can use if or whether to relate indirect yes-no questions and questions with or. If is more common than whether: Please contact the manager if you have any further queries. I called Amelia to find out whether she really did go to movie or not.
If = We use if to introduce a clause, often in indirect speech, that shows two or more possibilities: Mr. William called to ask if his ticket was booked. I don’t care if he stays or not – I’m coming! Mrs. Wilson was wondering if you’d accompany her to the market this evening?
Whether = We use whether especially in reporting questions and expressing doubts. We use whether in more formal situations: The board will ask the chairman whether he would recommend this syllabus to the school from this year. (in a formal board meeting). The administrator read a letter that he’d written and the board discussed whether the matter should be closed.
We prefer ‘whether’ with ‘or’ when there is more than one alternative in the indirect question: After the meeting, members asked whether they should change these age-old policies, selection criteria or both.
To present a choice, we can use ‘or not’ with ‘if’ and ‘whether.’ In this case, ‘whether’ is immediately followed by ‘or not’ or in end position. With ‘if’, we use ‘or not’ in end position only: I called Jack to find out whether or not he really did want to marry Isabella. I called Jack to find out if he really did want to marry Isabella.
Whether or not = means “regardless of whether”: She’s going to complain whether or not the principal accepts her demand. (= no matter what the principal does, she will complain)
Typical errors: If, whether
We use ‘whether’ and not ‘if’ before a to-infinitive, often when we’re referring to future plans or decisions:
I was wondering whether to go for a swim.
I don’t know whether to see ‘The Beekeeper’ or the ‘Mean Girls.’
Inform the counsellor whether you need help. (= two possibilities: you need help or you do not)
Inform the counsellor if you need help. (= you must inform the student adviser only in case you need help)
Let me know whether the wheel still jams. (= no matter whether the wheel jams or not, you let me know)
Let me know if the wheel still jams. (= in case the wheel jams, let me know about it)
He wants to find out if the cab has an extra passenger.
He wants to find out the cab has an extra passenger. X (if/ whether can’t be omitted)
Let me know if you need more time. (= … only if you need more time)
Let me know whether you need more time. (= … whether you need more time or not, you have to inform me)
Whether not if
We use whether and not if after prepositions, infinitives, and as subjects and complements of a sentence:
We had a discussion about if we are having a party tonight. X
We had a discussion about whether we are having a party tonight. √
The jury seemed mainly interested in if there were any eye-witnesses to the murder. X The jury seemed mainly interested in whether there were any eye-witnesses to the murder. √
We use whether, not if, directly before or not:
Can you tell me whether or not you’re interested in this project. √
Can you tell me if or not you’re interested in this project. X
I’m not interested in whether I get a window seat and that kind of thing, I just want to have a confirmed booking. √
I’m not interested in if I get a window seat and that kind of thing, I just want to have a confirmed booking. X
We prefer whether when introducing a subject or a complement in a sentence:
The question is whether the show will click.
The question is if the show will click. (if as a complement is also possible, but less common)
I doubt if/ whether = I doubt if/ whether he can catch the train on time. (both are possible)
I don’t know whether = I don’t know whether he didn’t hear the bell or (whether) he just didn’t want to speak to me.
Remember if and whether are often interchangeable, but have noticeable uses. For clarity, it is highly recommended to use whether in reference to a choice or alternatives (“we’re moving out whether they cut back on rent or not“) and if when establishing a condition (“we’re moving out if they don’t cut back on rent“).
Example sentences of if and whether
I don’t know if/whether the parcel has arrived.
I am not sure if/ whether the party is already over.
I’m not sure if/whether my suggestion will be accepted.
I don’t know if/whether I should tell mother this.
I’m not sure if/whether she’ll admit her fault.
I’m not going to the cinema whether he pays or not.
The police officer wondered if/whether his story was true.
They doubt if/whether the team will win all upcoming matches.
We wonder if/ whether tomorrow’s exam will be postponed.
They doubt if/whether they will share the news with the rest of us.
Some more example sentences of if and whether
I don’t know if he can drive to the mall. He is probably sleeping off a mighty hangover.
They didn’t comb and brush their dogs, and got them pruned for the beauty contest this year so I doubt if they’re going to win it.
He called the manager to see if/whether they take reservations at this time of the year.
We had plenty of evidences to show them but I’m not sure whether they’ll be able to admit any of them.
Amelia called the bakeries nearby and found out if any of them sell Blueberry Muffins.
He called Jack from the airport and asked if he could drop in to see him before check-in.
We’re having a conversation about whether their plan would succeed when everyone else failed.
The jury has not decided whether the next hearing will be held in February or March.
