The difference between “who” and “whom” can be tricky, even for experienced writers. The word “whom” is rarely used in casual conversation anymore, so “who” often sounds correct, even when it isn’t.
Once you know how these relative pronouns are meant to work in a sentence, you’ll be on your way to correctly choosing between who and whom—or on your way to mindfully breaking the rules. Let’s dive in, shall we?
What’s the difference between who and whom?
Put simply, “who” is the person who does an action, and “whom” is the person who receives the action or its effects.
In grammatical terms, “who” is a subjective pronoun, meaning it refers to the subject of a sentence or clause:
“Aunt Marianne is a palm reader,” said Hannah.
“Wait, who’s a palm reader?” asked Rich.
“Aunt Marianne, the subject of my sentence!” said Hannah.
In Rich’s question, the word “who” refers to Aunt Marianne, the subject of Hannah’s sentence. In contrast, “whom” is an objective pronoun, meaning it refers to the object of a verb (an action word) or preposition (a word that indicates relationship, direction, time, place, or location):
“I’m giving a palm reading to Rich tomorrow,” said Aunt Marianne.
“To whom?” asked Hannah.
“To Rich! He’s the object of my favorite verb phrase, ‘to give a palm reading.’”
As Aunt Marianne helpfully pointed out, Rich is the object of the verb phrase in her sentence, so Hannah refers to him using the objective pronoun “whom.”
In order to confidently master the use of who versus whom in complex sentences, it helps to also understand the purpose of relative pronouns.
Relative pronouns and how they work
Even if you’re unfamiliar with the concept of relative pronouns, you’ve definitely used them before: the most common relative pronouns are who, whom, whose, which, and that.
A relative pronoun is a word that connects a bit of descriptive information to a person, place, or thing. “Who” and “whom” are relative pronouns that typically refer to a person, while “which” and “that” are relative pronouns that typically refer to a place or thing.
Sarah, who is an award-winning journalist, broke the story of the scandal.
Sarah is the subject of the sentence, and the part of the sentence where we’re told that she’s an award-winning journalist is what’s called an adjective clause. The relative pronoun “who” connects it to the subject of the sentence, Sarah.
“Whom” also connects adjective clauses to something.
She concealed the name of her source, from whom she got a scoop about the disgraced Mayor.
Here, the relative pronoun “whom” connects the adjective clause in the sentence to the object of the sentence: Sarah’s source.
Now that we know that both “who” and “whom” connect descriptions to things, let’s take a look at the rules for deciding when to use “who” and “whom.”
The rule of who
We’ve learned that “who” is a subjective pronoun because it refers to the subject of a sentence or clause, which is the person or thing doing an action. The simplest rule is that if we rephrase a sentence into a question, “who” can be swapped with other subjective pronouns such as I, he, she, we, or they.
Sarah is the journalist who/whom broke the story of the scandal.
Whom broke the story? Her did.
Who broke the story? She did.
See how we turned the phrase into a question that we are only able to answer correctly using “she”? That means that the right choice for our original sentence is “who.”
It’s not possible to answer the question using “her”; the answer to “Whom broke the story?” can’t be “her did”–that obviously sound wrong.
Since we used “she” in our rephrased question, “who” is the right choice in our original sentence. If we had been able to answer our rephrased question with “I,” “he,” “we,” or “they” instead of “she,” then “who” would also have been correct.
The rule of whom
In turn, “whom” is an objective pronoun because it refers to the object of a verb or preposition. The object is usually a person to whom an action is being done. Therefore, if we can rephrase a sentence into a question that we wish to answer, “whom” can be swapped with other objective pronouns such as me, him, her, us, or them.
The anonymous source, from who/whom Sarah learned about the scandal, was kept a secret.
From who did Sarah learn about the scandal? From I.
From whom did Sarah learn about the scandal? From me.
In this example, we rephrased the sentence into a question, and that question can only be answered with “me.” The answer to “From who did Sarah learn about the scandal?” can never be “from I” or “from he”–those sounds wrong. Therefore, “whom” is the right choice for the original sentence.
Another tip to remember is that “whom” is always the correct pronoun to follow any preposition. The prepositions from, to, with, and by are commonly followed by “whom.”
The mayor and an associate have been accused of laundering money.
Laundering money from whom? With whom? To send to whom? And he was elected by whom?
Examples of when to use who and whom
Now that we’ve learned the rules, let’s take a look at some more examples of who vs. whom to help you apply these rules to your writing. The examples that follow are common conundrums when it comes to who vs. whom.
By who or by whom?
Let’s say you heard a song on the radio, and you’d like to ask about the name of the artist.
You probably wouldn’t ask “By who is this song?”, simply because that sounds incorrect to a native English speaker’s ear.
You could probably ask “Who is this song by?” without being corrected, even though ending the sentence with a preposition (by) is technically incorrect.
Even though it sounds more formal, the grammatically correct phrasing is “By whom is this song?” This is because “by” is a preposition, and as we learned above, “whom” (not “who”) always follows a preposition.
Correct: By whom is this song?
Incorrect, but casually accepted: Who is this song by?
Incorrect: By who is this song?
For who or for whom?
Have you read Hemingway’s novel For Who the Bell Tolls? No, you haven’t—because “for” is acting as a preposition, so the correct title of the book is For Whom the Bell Tolls.
To expand on this example, let’s use the trick we learned above and answer Hemingway’s title as if it were a question, keeping in mind the rule about subjective and objective pronouns.
If you asked “for whom does the bell toll?” The answer could be that it tolls for me, him, her, us, or them (or, as poet John Donne famously wrote, it tolls for thee). Since only objective pronouns can replace the relative pronoun here, the relative pronoun should also be objective (in other words, whom).
So, “for who does the bell toll?” It definitely doesn’t toll for I, he, she, we, or they. Since the question cannot be correctly answered using a subjective pronoun, the relative pronoun cannot be subjective (in other words, who).
How strict is the who vs. whom rule?
You’ve probably noticed that any use of “whom,” even when it’s correct, sounds formal and maybe even a little dated. That’s because this rule has fallen out of favor for casual English speakers, who might ask “Who is this song by?” or “Who is the bell tolling for?” or even “Who did Sarah get that scandalous scoop from?!”
Despite this, it’s still best practice to use “who” and “whom” correctly in written communications for the sake of clarity. While it’s uncommon, it’s possible for incorrect relative pronouns to confuse your reader and obscure your intended meaning.
If you’re writing dialogue, however, an intentionally fudging this rule can make a character sound more casual, or if your setting is modern, can make dialogue sound more authentic. Just be sure to use who vs. whom correctly in your narration (as opposed to your characters’ dialogue) so that your prose is clear and unambiguous.
Who vs. whom: the final verdict
Next time you find yourself in doubt over when to use who vs. whom, remember the rule of thumb that if you rephrase your sentence, who can only be replaced by he/she and whom can only be replaced by him/her (or whichever other pronouns, like I/me or they/them, make sense in the sentence you’re working on). It’s a simple rule, but it’s easy to remember and it works every time!