When adressing a group of people and wanting to find out who belongs to a certain subgroup, is it correct to use "who of you" or "which of you" at the beginning of the question? For example, would you use:

Who of you knows what the obliqueness of the ecliptic is?


Which of you know what the obliqueness of the ecliptic is?

EDIT: What about

Who of you know what the obliqueness of the ecliptic is?

  • Did you change the verb inflexion from knows to know on purpose or was that just a typo?
    – Yay
    Jan 4, 2016 at 14:09
  • @Yay that was on purpose. Intuitively, it seemed right to me. Isn't it?
    – user159517
    Jan 4, 2016 at 14:13
  • I cannot tell about "intuition" since I'm not a native English speaker. I just found it curious that if 'who' and 'which' really are interchangeable (at least in this context), then why does one take a singular inflection and the other take a plural one? Or rather, does "which of you know...?" somehow imply there will be more than one who will know, while "who of you knows...?" or "which one of you knows...?" doesn't? But I guess this is more a question for @Ricky or any other answerer.
    – Yay
    Jan 4, 2016 at 14:23
  • That were my exact thoughts, namely that "which of you know..." suggests there are several people who could know while "who of you knows" as well as "which one of you knows" suggests there is one person who knows.
    – user159517
    Jan 4, 2016 at 14:29
  • "who amongst you ..." would work. "who knows ...". "which of you knows ...".
    – simbo1905
    Jan 4, 2016 at 19:33

4 Answers 4


Simpler is best. "Who knows what the obliqueness..." is the simplest way to get your point across, and therefore preferable.

Alternatively I might say "Who here knows what the obliqueness..." or "Do any of you know what the obliqueness..." The best option of all may be "Who can explain what the obliqueness..." as it seems likely that you actually want to know whether or not any of your students can explain the concept to the class. If that is indeed what you really want to know, then it's best to ask that question.

I would not use which in this situation because it doesn't sound right to me. I have used this internalized system derived from years and years of reading many books in English, and it has served me very well on standardized tests as well as in the real world. I'm from the South in case some sort of regional variation is at play here.

I think who is preferable because there's a distinct possibility that no one is going to be able to answer the question. As a parent at home alone with two kids you would ask them "Which one of you turned on the microwave with nothing inside?" You KNOW it was one of them. "Who turned on the microwave..." isn't wrong, but it implies that you have no idea who did it as opposed to knowing that it was one of two options.


For what it's worth, I'd say

Which of you know ...


Which one of you knows ...


Does any one of you know ...


Does anyone here know ...

Suggested by @Chase Sandmann (indeed, this one is the most natural-sounding of the group):

Do any of you know ...

"Who of you" sounds awkward.

  • I'd say that only the first one really has the exact same meaning as the original question, even though I think one can use all of the phrases you gave interchangeably in every normal conversation. So I'd conclude that in your opinion, "Which of you" is correct.
    – user159517
    Jan 4, 2016 at 14:21
  • 1
    @user159517: You do that.
    – Ricky
    Jan 4, 2016 at 14:29
  • I would add "who amongst you knows ..." but thats not a very common way to say it.
    – simbo1905
    Jan 4, 2016 at 19:30
  • 2
    "Do any of you know..." would be my sentence of preference. Jan 4, 2016 at 21:27
  • @ChaseSandmann: You're absolutely right. Just made the appropriate edit, crediting the source.
    – Ricky
    Jan 4, 2016 at 22:10

"Who" is a pronoun that can exactly mean "which."

Both of your sentences are equally correct. Both are common. Neither is preferable to the other.

  • So there is no situation where using "who" is more appropriate than "which" or vice versa? The curious thing about this is that I had native speakers tell me "who" is correct and "which" is false while others claimed the opposite was true. Maybe there's a connection with local parlance.
    – user159517
    Jan 4, 2016 at 14:07
  • Yes, there are situations where "who" is more appropriate than "which." For example: "This is my best friend, who just moved back to town." In the quoted sentence, "who" is more appropriate than "which". Jan 4, 2016 at 14:12
  • Can you outline some sort of general rule behind this?
    – user159517
    Jan 4, 2016 at 14:16
  • The rule of thumb to use is this: If you can replace "who" with "which one of" and have it still make sense, then you may use "who" and "which" interchangeably. Jan 4, 2016 at 15:50

English as she is spoke

It's important to remember that good English is more than just correct syntax and grammar. It is equally about clarity of expression, contextual understanding, customs, tropes, clichés, rhythm and sonic texture. It also evolves: almost nobody today speaks in the same way as their Victorian forebears.

Full of sound and furry

When we hear speech, we don't pay attention to individual words, but to the sounds they make. We understand meaning because we subconsciously pattern-match those sounds to existing chunks we've already stored away in our brains from countless prior conversations, each of which carries snippets of meaning both individually and also when combined. The more differentiated those sounds are, the less we have to think to derive meaning. Conversely, if we come across an uncommon, ambiguous, or unusual sound, it doesn't immediately register and we can experience a momentary discomfort while we regain our bearings. Fundamentally, for some people, the problem with 'who of you' is not grammar, but the noise it makes.

The funky gibbon

The two long 'o's in 'who' and 'you' are separated by a single short word also beginning with 'o'. Moreover, there are no hard consonants or sibilants to break up the phrase. When spoken therefore, the overall sonic effect is "oo-o-yoo", or perhaps something like "oo-a-yoo", depending on pronunciation. Apart from sounding like a monkey, this is a lot like the sound made by the question "who are you?", which is an extremely common sound-meme. This switching of the common translation of the sound for a different one may be the reason it feels a bit awkward, as Ricky suggests. For a brilliant example of this see the Two Ronnie's sketch 'Four Candles'.

Finally, returning to the question

Which of you watched Sherlock at Christmas?

Who watched Sherlock at Christmas?

  • sorry is the funky gibbon good or bad? it is not clear if you are saying to avoid it or not.
    – simbo1905
    Jan 4, 2016 at 19:33
  • The funky gibbon (hylobates fungosam) is morally neutral, being neither a goodie nor a baddie. Whether you choose to dance or not depends on whether you like the song it sings.
    – Vince
    Jan 4, 2016 at 22:06

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