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GMAT Sentence Correction: If vs. Whether

“I don’t know if you will find this post helpful”

Do you spot the error in the preceding sentence?  This error is common in casual spoken English, but it will cost you on the GMAT Sentence Correction.  In that sentence, the word “if” is incorrect: it should be replaced by the word “whether.”


When to use “if”

The word “if” is used for clauses that specify conditions or speculate on something hypothetical.

1.) Condition: “If you finish your peas, you can have dessert.”

2.) Hypothetical: “If I regularly ate my vegetables, I probably would be healthier.”


In formal logic, the clause following the “if” clause would begin with the word “then”: that’s perfectly acceptable grammatically, but not at all necessary.  For example, in both of those sentence, the word “then” could be inserted right after the comma, and would add a bit of emphasis to the logical relationship, if that were something that needed underscoring.

The last clause of the previous paragraph highlights a particular category of conditional statements, those using the subjunctive.  For more on the subjunctive mood, see this post.  The GMAT loves “if”-clauses involving the subjunctive.


When to use “whether”

The word “whether” is a relative pronoun, which means it introduces a relative clause.  A “whether” clause is always about the uncertainty in a choice or alternative, and the clause itself may stand apart from the sentence, the way an “if” clause does, or may act as a noun.  When it stands apart, it is like an “if” clause in which the definite causal nature has been replaced with uncertainty or irrelevance.  When it acts as a noun, the clause may act as the subject of the sentence, or as the object of an epistemological verb (to know, to wonder, etc.)  or a volitional verb (to care, to prefer, etc.)


Stands apart:

3.) Whether you study French or Spanish, you will encounter an unfamiliar language in Japan.

4.) Whether or not I get the raise, I am going to buy that new car.


Notice, in either of those: if we removed the uncertainty of the choice, we could replace the word whether with the word “if” to get a more definitive conditional statement.  Without making those changes, the word “if” would be wrong.


Subject of sentence:

5.) Whether you like jazz will influence your opinion of this new club.

6.) Whether I walk on her left or right side matters a great deal to her.


Object of an epistemological or volitional verb:

7.) I don’t know whether there is intelligent life elsewhere in the Universe.

8.) He doesn’t care whether you serve broccoli or Brussels sprouts with dinner.


In sentence #5-8, the word “if” would be 100% incorrect.   The GMAT Sentence Correction loves to test that particular mistake.


Whether . . . or not

The word “whether” implies a choice, at least a pair of alternatives.  Sometimes that choice is made explicit (as in sentences #6 and #8), and sometimes it is implicit (as in sentences #5 & #7).  When the choice is implicit, is it grammatically correct to add the words “or not” after whether?

When the “whether” clause acts as a noun, the words “or not” add absolutely nothing to the sentence. Consider:


5a.) Whether you like jazz will influence your opinion of this new club.

5b.) Whether or not you like jazz will influence your opinion of this new club.


The meaning of both sentences is exactly the same.  The second sentence adds two more words that contribute zilch to the overall meaning of the sentence.  What is GMAC’s opinion of tossing in extra words that lengthen the sentence and contribute bupkis to the meaning?  As you may well guess, they frown on these.  Don’t expect to see “whether or not” in any correct GMAT SC answer choice when the clause is used as a noun.

When the clause stands apart, as in sentences #3 & #4, that’s another matter.  In that construction, the alternative must be made explicit.  In #3 there already was an explicit comparison of the two languages, but in #4 we absolutely must include the words “or not” after the word “whether”: the grammatical construction demands it.  This is the only case in which the words “whether or not” could be correct on GMAT sentence correction.

Whether or not you like it, knowing the correct use of “whether” and “if” is important for GMAT Sentence Correction.  If you can master these distinctions, you will perform well on a question that that befuddles many.

Two relevant SC questions in the GMAT Official Guide, which appear as:

a.) #34 & #75 in OG12e, and

b.) #34 & #78 in OG13e

By the way, sign up for our 1 Week Free Trial to try out Magoosh GMAT Prep!

22 Responses to GMAT Sentence Correction: If vs. Whether

  1. Sergey Kharlanov July 23, 2015 at 7:36 am #

    Hello Mike. Thanks for this article. This is always pleasure to read your explanations.

    But I have some confusion about this topic.

    I found in Oxford dictionary such phrases:

    “I’m going whether you like it or not.”

    And also in Manhattan book:
    “I decided to eat the food, WHETHER it was tasty OR NOT.”

    And in NYtimes article on this topic:
    “They will play tomorrow whether or not it rains”

    Could you please clarify. This is some sort of styling that will be wrong on the GMAT or maybe these examples are exceptions from the rule?

    Thanks in advance.

    • Mike McGarry
      Mike McGarry July 24, 2015 at 10:14 am #

      Dear Sergey,
      I’m happy to respond. :-) Here’s what I will say. The “or not” is optional, NOT necessary to the structure. It is perfectly fine include for clarity: it is always included in colloquial conversation, and it makes sense that the NYT would include it for this reason as well. I believe the OED was quoting colloquial speech in that instance, and even that MGMAT sentence is far too colloquial in subject to appear on the GMAT. I suppose including the “or not” *could* be part of a correct answer on the GMAT SC, but I have never seen the “or not” used except in wordy incorrect answers. You can rest assured that the GMAT will NOT make you decide between two versions that differ only in the presence or absence of the “or not.” It’s simply important to appreciate that we can use “whether” without the “or not.”
      In all three sentences you cite here, there is something colloquial. In all three, simply removing the “or not” would make it sound awkward. Instead, the more well-spoken way to say any of these would be to replace “whether or not X” with “regardless of whether X.” For example:
      “They will play tomorrow, regardless of whether it rains.”
      That’s a tad more formal, and the GMAT SC tends to aim for that level.
      Does this make sense?
      Mike :-)

  2. Caleb May 16, 2015 at 3:53 am #

    Hi Mike,

    Love the detail and clarity of your posts. My question is whether there is any correct usage of “whether..or not”. If there is any correct usage, then what is the form?

    For example, in the signing off paragraph, it says “whether or not you like it, knowing the correct…” I would tend to say it as “whether you like it or not, knowing the correct…”

    • Mike McGarry
      Mike McGarry May 18, 2015 at 4:21 pm #

      Dear Caleb,
      In spoken English, “whether or not” is often used for clarity and emotional emphasis. It’s perfectly fine for those purpose in spoken English. Remember, the writing on GMAT SC is stodgy, unemotional, academic writing. There’s no room for the spice of emotional inflection in this writing. The construction “whether or not” has absolutely no place in the GMAT SC. It’s redundant and would not appear. Your question concerns the correct use of something that would never be used on the GMAT.
      In the last paragraph, I was being colloquial and casual. In casual writing, either version would be acceptable:
      (a) whether or not you like it,
      (b) whether you like it or not,
      Arguably, they have slightly different emotional inflections, but for colloquial purposes, both are acceptable. For GMAT purpose, neither would ever appear, so it’s irrelevant.
      Does all this make sense?
      Mike :-)

  3. Sudipt August 20, 2014 at 2:48 am #

    Hi Mike,

    Been following your content on this website and have found it extremely useful.

    It puts all the important things forward in a very simple manner, something I have not found anywhere else on the web.

    Just a question – does Magoosh have online classes for the Verbal section of GMAT ?



    • Mike McGarry
      Mike August 20, 2014 at 9:57 am #

      Dear Sudipt,
      Yes, absolutely! We have a full set of Verbal video lessons, including a recently revised series on GMAT SC, and each practice question has its own video explanation — these accelerate the learning process with immediate feedback. If you click on the ad at the top “Learn More about Magoosh GMAT Prep”, you will be led to our plans page.
      Mike :-)

  4. zish July 15, 2014 at 5:35 am #

    Hi mIke

    What i got from this is that when Whether is used as a subordinate clause ,we cannot replace it with “if”, and when whether clause is used as a subject or object of verbs then it is replaceable by ‘”if”. Am i correct?

    • Mike McGarry
      Mike July 15, 2014 at 2:52 pm #

      Dear Zish,
      I’m happy to respond. :-) Unfortunately, my friend, that is not entirely correct. First of all, both “whether” and “if” begin subordinate clauses, so that is not a good way to distinguish them. Further, a clause that used as a subject is a substantive clause, which is one category of subordinate clauses, and these definitely need to begin with “whether” — an “if” clause can NEVER be the subject of a sentence. For the most part, what distinguishes the correct use of “if” from the correct use of “whether” is not grammar but LOGIC. You need to understand in depth the logical distinctions discussed in this article.
      Does all this make sense?
      Mike :-)

      • Zish July 15, 2014 at 3:55 pm #

        Thanks mike

        • Mike McGarry
          Mike July 15, 2014 at 4:02 pm #

          Dear Zish,
          You are more than welcome. :-) Best of luck to you!
          Mike :-)

  5. Jay June 9, 2014 at 8:16 pm #

    Hi Mike,
    I’ve been following your blog posts lately. They have been tremendously helpful.
    I have a question from the post. You mentioned that the words “or not” will add no meaning to “whether” that acts as a noun. (Example given is “whether (or not) you like Jazz….”). Does the same concept apply toward “whether” that acts as an object of volition or epistemological verb? I assume that will be the case, but I just wanted to be sure… Thank you.

    • Mike McGarry
      Mike June 10, 2014 at 10:14 am #

      I’m happy to respond. :-) In spoken language, in colloquial English, the “or not” would often be used for rhetorical clarity — “I don’t know whether or you are planning to come to my party.” In the formal writing of the GMAT SC, this will not happen. The “or not” will be wrong 100% of the time on the GMAT.
      Does this make sense?
      Mike :-)

      • Jay June 10, 2014 at 4:31 pm #


        Totally. Thanks!

        • Mike McGarry
          Mike June 11, 2014 at 10:11 am #

          Dear Jay,
          My friend, you are quite welcome. Best of luck to you.
          Mike :-)

  6. Confuse Mind August 16, 2012 at 7:44 pm #

    Just one clarification-

    By stand apart – you mean 2 complete clauses are connected, right?

    • Mike McGarry
      Mike August 17, 2012 at 3:03 pm #

      I’m not sure what you mean be “connected.” By “stand apart”, I mean the “whether” clause is separated from the rest of the sentence by a comma, and what follows is a complete independent clause. Unlike the subsequent examples, the whether clause is not playing a role (subject or direct object) in the main independent clause of the sentence. Are we saying the same things?
      Mike :-)

  7. Abhi June 8, 2012 at 10:15 pm #

    Sorry, I don’t understand how the following sentence cannot have “if”:
    “I don’t know whether there is intelligent life elsewhere in the Universe.”

    Replacing “whether” with “if” also sounds correct:
    “I don’t know if there is intelligent life elsewhere in the Universe”

    • Mike McGarry
      Mike June 10, 2012 at 4:10 pm #

      Abhi: the trouble is — this is a *very* common error in spoken English. The mistake is more common than the correct construction in spoken English. This is why the incorrect construction, with “if”, *sounds* correct. It’s not correct. This is also why the GMAT loves testing this concept, because when people don’t know the grammar and just rely on what sounds natural, they will be wrong. Does that make sense?
      Mike :)

      • Abhi June 21, 2012 at 7:07 pm #

        Thanks, Mike. Yes, I realized I have been making this mistake myself, while speaking, since a long time now. Good to clear it up.

        • Mike McGarry
          Mike June 22, 2012 at 1:12 am #

          I’m glad I was able to help. Best of luck to you.
          Mike :)

  8. Komal May 29, 2012 at 10:56 am #

    It was great help, as I had always confused with “Whether or not” issue. Now I understand why “Whether or not ” is correct. Thank you.

    • Mike McGarry
      Mike May 29, 2012 at 2:55 pm #

      I’m glad you found this helpful. Let us know if you have any further questions.
      Mike :)

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