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What's the rule for using “who” or “whom”?
With who vs. With whom

Are “by whom?” and “who by?” perfect equivalents?

I have the feeling that the use of “who by?” is just a way of avoiding use “whom” but I have no evidence or proof. The anglophone people I talk to hardly use “whom”.

Are both expressions equally used, or is the difference between them only regional?

  • 3
    You may find the answer here: english.stackexchange.com/questions/56/… Feb 8, 2012 at 15:13
  • Voting to close too, even though I've answered. Can't resist an opportunity to knock the 'whom' fetish. Feb 8, 2012 at 17:12
  • @BarrieEngland I don't think is a “exact duplicate“; my question is more about “who by?” as a replacement for “whom”, not about “whom” usage.
    – pferor
    Feb 8, 2012 at 17:33
  • @BarrieEngland, as pferor says, this is definitely not an exact duplicate. However, I do not have enough rep to vote to reopen.
    – dainichi
    Aug 11, 2012 at 3:38

4 Answers 4


They're not perfect equivalents, but they're pretty close. The biggest difference, of course, is that whom is a pretty formal word, so "By whom?" is a very awkward reply to, say, "He got f'd." Either "By who?" or "Who by?" would be much more natural.

Another difference is that if someone uses a by-phrase that you didn't quite catch, or that you're surprised about, you can reply "By whom?" or "By who?", but not "Who by?", to request a repetition. ("By who?" is the most common wording in this case: "This book is by Mr. Aasefalsdfjaose." "By who?")

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    I have no idea that speaking correctly make it formal. Feb 8, 2012 at 15:39
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    Using archaic words can be considered "formal". While whom is perhaps not yet archaic, it is going rapidly.
    – GEdgar
    Feb 8, 2012 at 15:44
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    @speedyGonzales: For a great many native speakers (quite possibly even the majority), any use of "whom" would be considered formal, regardless of whether it's "correct" by traditional grammar. In the more general case many idiomatic usages aren't strictly grammatical, but the correct version is considered more formal (e.g. - "Can I come in?" compared to "May I come in?"). Feb 8, 2012 at 16:59
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    @Jay: In traditional grammar (the sort with made-up rules like "don't end a sentence with a preposition"), the "in" in "come in" is not called a "preposition" at all, but an "adverb" or "particle". (In traditional grammar, it's only called a "preposition" when it has an object, as in "in the office" or "in reality".)
    – ruakh
    Feb 9, 2012 at 18:32
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    @Jay: I think "don't end a sentence with a preposition" is actually a kind of "urban myth". I've never met any teachers (even quite old ones) who would endorse the so-called "rule", and I'm convinced everyone who claims to have been taught it in school is simply suffering "false memory syndrome". Plus it's a racing cert Churchill never said/wrote This is the sort of pedantic nonsense up with which I will not put Feb 9, 2012 at 18:36

"By whom?" is correct. "Who by?" is incorrect, though it is commonly used, especially in speech as opposed to writing. Actually I suspect the most commonly used expression would be "By who?" "Who by?" is really doubly incorrect because it both uses the wrong form of the word "who" and it puts the object of the preposition before the preposition.

To those who say that correctness is determined by popular usage and that "whom" is becoming obsoleete: Yes, but usage by whom? (Or "Usage who by?" if you prefer.) "Whom" is still considered the more literate and correct word to use. If you want to sound intelligent, write "by whom". If you're chatting with your buddies at the bar, it doesn't matter.

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    I see what you did there... Great answer. Thank you!
    – airstrike
    Oct 23, 2016 at 21:49

Whom and who in object position or in a prepositional phrase are both grammatical in Standard English. The difference is one of formality, with whom being used in the most formal contexts. ‘The Cambridge Grammar of the English Language’ says all that needs to be said on the matter on pages 7 and 8 here.


I've heard of "who by" for the first time! It is, naturally, grammatically incorrect. However, like @speedyGonzales said, it is okay to use it for spoken English. But I've only heard of "by who".

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