Whether or If

WHETHER - IF

'Whether' and 'if' are used as follows:

·         To introduce a yes/no question:

o   He asked me whether/if I felt well.

·         To report a question :

o   Are you going to the party?
- She asked me whether/if I was going to the party (or not).

·         To express alternatives:

o   I don't know whether/if I'll go to the party on Saturday (or not).

With whether we can use 'or not'  immediately after whether, or at the end of the sentence.
With if we use 'or not' in end position only.

• I called Susan to find out whether or not she was going to the party.

o    I'll be happy whether or not we go to the party.

• I called Susan to find out whether/if she was going to the party or not.

WHETHER

Whether is considered more formal than if.

·         John read a letter that he’d written and the board discussed whether it should be mailed.

The verbs discuss and decide generally take whether rather than if

Use "whether" when you are showing there are two possible outcomes (using the word "or").

o  Charlie didn't know whether to call or to find out about her plans.

o  He didn't know whether Ann was going to the beach or the mountains for the weekend.

Ø  We use only whether

• When followed by an infinitive :

• I don't know whether to go to the party or not.
• Charlie didn't know whether to invite Alice to the party on Saturday

o    I was wondering whether to go for a swim.

• After prepositions:

• It depends on whether I get home early or not.
• The police seemed mainly interested in whether there were any locks on the windows.

IF

·         Use "if" when you have a conditional sentence.

o   What would Max do if he lost his job?

o   I'll come to your party if you invite me.