# Usage of "If vs whether"

Test questions (Source: “Quiz your English” - an app by Cambridge):

1. “When we have been overwhelmed with emails, we wonder ________ we might have missed something important by dealing with them quickly.”

a.weather

b. whether

c.wether

d.if

1. “A librarian can help you if you are wondering _____ a source has the information you need.”

a. if or whether

b.if or not

c. whether

d. whether or not

1. b – whether
2. d – whether or not

My question: Why can't we also use the answer “d” in the first question and the answers “a, c” in the second question (by the answer “a” I mean either if or whether)?

P.S. I've heard about the rules governing the usage of “if vs. whether” (https://dictionary.cambridge.org/grammar/british-grammar/if-or-whether ), but I'm not sure which one applies here.

• By analogy with question 2 answer d. I think by answer 2-a they meant this: "... wondering if or whether a source has...", and that would be wrong. Aug 11, 2020 at 21:35
• If and Whether are often used repetitively. Thus, a) is wrong. As for que.1, meanings of the options should get you the answer. Aug 12, 2020 at 2:12
• In 1. both "whether" and "if" are fine, and in 2. "if", "whether" and "whether or not" are all fine. Don't trust the quizz answers! Btw, are you sure you understood the answers correctly? Aug 12, 2020 at 14:07

“When we have been overwhelmed with emails, we wonder whether we might have missed something important by dealing with them quickly.”

In this case, whether and if are interchangeable. In both cases, there are two possible outcomes implied - either we missed something important, or we didn't.

“When we have been overwhelmed with emails, we wonder whether or not we might have missed something important by dealing with them quickly.”

Using whether or not is viable here too. It is equivalent to saying "When we have been overwhelmed with emails, we wonder whether we might have missed something important by dealing with them quickly or not." Instead of implying the two outcomes, they are being explicitly stated.

“A librarian can help you if you are wondering whether a source has the information you need.”

This is actually the same principle as the prior examples. There are two outcomes implied - a source has the information you need, or it doesn't. You can use whether or whether or not interchangeably. The only reason not to use if here is because it was already used earlier in the sentence and would sound unnatural.

Neither of these examples have both outcomes explicitly stated in the sentence. Take this sentence for example:

We don't know whether Julie will arrive on Monday or Tuesday.

The sentence explicitly states two possibilities, one of which will occur. Julie will either arrive on Monday or Tuesday.

We don't know if Julie will arrive on Monday or Tuesday.

Depending on how this is read, there is now a third option - maybe Julie won't arrive at all.

In this case whether more clearly conveys the intent.

• Great answer! Welcome to ELL and thanks for putting in the time and effort! Aug 28, 2020 at 5:14
• @EddieKal Thanks for having me! It's my pleasure :)
– mjjf
Aug 28, 2020 at 5:18
• Oops - I accidentally awarded 50 rep to another answer. But I like this one, and if it is possible to reward it, I will gladly do so.
– Zak
Aug 31, 2020 at 6:23
• @Zak Unfortunately there is no way anybody can change the bounty reward. That is the rule and when you click the reward I believe you were warned about the rule. Aug 31, 2020 at 6:57

The answer to (1) is incorrect in casual American English. Both whether and if would work there, and if is probably more common. Similarly in the second question, both 'whether' and 'whether or not' would be acceptable in casual speech.

• Who decides what is correct in casual English? Aug 12, 2020 at 6:02
• In the Old English these two words, being of different origin, carried different meaning: “if” (from “gif” meaning so or if) introduced a condition; “whether” (from “hwæther” which means which of two) introduced an alternative. And indeed, in some cases, using “if” instead of “whether” would be strange: “I'm coming if you like it or not!”;). However if native speakers feel that in most cases “if” and “whether” are interchangeable, then “Vox Populi, Vox Dei”.
– Zak
Aug 25, 2020 at 14:29
• @MichaelHarvey (B) in Question #1 is certainly not incorrect in informal AE. We use it all the time. Aug 31, 2020 at 0:08
• @BadZen, if that was a reply to me, I was not saying you can't use 'whether', I was saying that both whether and if were OK. Sep 1, 2020 at 20:03
1. b and d
2. c, d or just "if"
• Hi welcome to ELL! We expect the answers to be detailed and well-explained. Please tell us why you suggested these choices. Aug 30, 2020 at 16:09