The Difference between If and Whether – Meaning

Though children have this misconception that both ‘if’ and ‘whether’ can always be used interchangeably, it’s not entirely correct. Both these words, though used as conjunctions, have different meanings. On the one hand, the term ‘whether’ is used to introduce a formal tone to the sentence and in the case of alternatives. Whereas the word ‘if’ is used when there are more than two chances of an alternative or when giving conditions. For example, “If Mira studies well, her parents promised her a laptop.” Here, ‘if’ is used to show that Mira’s parents promised her a gift on the condition that she studies well. Whereas “I don’t know whether I should go to the party.” Here, ‘whether’ is used to show that there are two alternatives, i.e. either I go to the party or I don’t go to the party. Once students catch this point of difference, it will be easy for them to use these conjunctions correctly.

If and whether are sometimes interchangeable, but not always. And the easiest way to avoid errors is to follow this simple rule: use if to introduce a condition. In all other cases, use whether.

But there’s still more to know if you want to use if properly. In fact, using the wrong word could change the meaning of your sentence entirely. So, keep reading to discover:

• The difference between if and whether
• When to use whether
• When you can use both if and whether
• How does using if or whether sometimes changes the meaning
• Other important uses for whether

The difference between if and whether

As we just learned, generally, we use if to introduce a condition:

• If you see her, let me know.

And we use whether to talk about alternatives:

• Do you know whether she’s coming (or not)?

This is a general rule that will help you avoid making mistakes. But remember, we can also use if to introduce alternatives:

• Do you know if she’s coming?

So how do you know which one to choose?

When introducing alternatives, your choice between if and whether will depend on two things:

1. If you want to sound more formal, use whether to introduce an alternative. Whether is generally preferred in a formal style:

• We discussed whether we should cancel the event.

2. When introducing more than two options, use if.

Let me illustrate this point with an example. Suppose I say,

• I don’t know whether the meeting is on Tuesday or Thursday.

Here we have two options. Tuesday is one option, and Thursday is another option. Now, when using if, I’m not limited to two options. So, I can say,

• I don’t know if the meeting is on Tuesday or Thursday.

But I can also say,

• I don’t know if the meeting is on Tuesday or Thursday, or if it’s next week.

So by using if, we allow for other options. But with weather, we’re limited to two choices.

When you can only use whether

In certain structures, only whether is possible. For instance, we use whether, and not if, after prepositions, infinitives, and as subjects and complements of a sentence. Here are some useful tips on when to use whether in English:

1. Use whether after a preposition

We don’t use if after prepositions. We use whether instead:

• We’re having a conversation about whether this would work.
• It’s not a question of whether it’s possible.

2. Use whether before infinitives

Before infinitives (to + verb), only whether is possible:

• But who knows whether to believe him?
• We had a discussion about whether to leave or not.

3. Use whether as a subject and complement

Whether is preferred when introducing a subject or a complement in a sentence:

• The question is whether it will last.
• Whether she was kidding was lost in translation.