How do I know when to use "who," and when to use "whom"?

Question

This question deals with the pronoun "whom," which can often be confusing even to native English speakers.

Answer 1

As easy way to remember the difference is that "who" basically does the same thing as "he" in a sentence. You can always rewrite a clause with "who" using "he."

For example: "who came to my house yesterday" = "he came to my house yesterday."

"Whom" can only be replaced by "him."

E.g. "whom we love" = "we loved him."

You would never say, "we loved he," so don't use "who" for a clause like this. The confusion arrises because most people don't observe this rule in daily speech, so a clause like "who we loved" doesn't sound wrong to most people, and that's why the "who/he" versus "whom/him" trick works really well.

I hope that helps.

Answer 2

The pronoun "whom," whether interrogative or relative, is in objective case. Whenever it functions as the object for another word, such as a preposition, the form "whom" is used. John Donne's famous poem, "For Whom the Bell Tolls" helps. In the title, "Whom" follows the preposition "For." It is the object of that preposition. The final line of the poem reads: "Therefore, send not to know for whom the bell tolls, It tolls for thee." Both "whom" and "thee" are in the objective case.

Also in the archaic greeting in a letter: "To Whom It May Concern," the objective case is used. Changing the word order to a question reads, "It may concern whom?" There you can see it is the object of the verb "concern,"

It is trickier when using it as a relative pronoun such as when used to introduce clauses in a sentence. Whether one uses "who" or "whom" in that case depends on its function in the clause.

Example. "He married a woman whom he had met online." The main clause is: "He married a woman." "Whom he had met online" is an adjective clause telling which woman--the one he had met online. "He" is the subject of the clause, and "whom" relates back to the "woman" who is the direct object of the verb met. Notice how I used the word "who" in my explanation? In that case. "who" is the subject of the adjective clause that I used.