If you are like many writers, choosing between “who” and “whom” can prove somewhat difficult at times. However, breaking down the words to their respective parts of speech and understanding the difference between them goes a long way in helping to determine which is correct. While both are used as interrogative and relative pronouns that replace a noun or personal pronoun, they are different types.
“Who” is a subjective pronoun. It replaces the subject of the verb, or the person performing the action the verb creates. When it replaces the subject of a question, it is an interrogative pronoun, and when it replaces the subject in a clause, it is a relative one. These attributes also apply to “whoever.”
“Whom” is an objective pronoun. It replaces the object of the verb, or the person the action created by the verb is affecting. It is an interrogative pronoun when it replaces the object in a question, and a relative one when it replaces the object in a clause. These attributes also apply to “whomever.”
When deciding which to use, it is important to remember that the difference between “who” and “whom” is the same as the difference between “I/me,” “he/him,” “she/her” or “they/their.” When you struggle with choosing which is grammatically correct, try replacing the “who” with “he,” and replacing “whom” with “him.” You can also rewrite the sentence to make it clear whether “he” or “him” is correct. Usually, the correctness of one over the other grows clearer as long as you remember that “he” replaces “who” and “him” replaces “whom.” Consider the following examples:
Example 1: That is who told me (rewritten: he told me – writing him told me is incorrect).
Example 2: Josh is whom you met last night. (rewritten: you met him last night – writing you met he last night is incorrect).
When “who” or “whom” starts a question, answer the question to determine which is correct following the same principle as that mentioned previously. Consider the below examples:
Example 1: Who is dancing? (Answer: He is dancing. “He” dictates that “who” is correct.)
Example 2: To whom is the letter addressed? (Answer: The letter is addressed to him. “Him” dictates that “whom” is correct.)
A dependent clause is one that cannot stand alone as a sentence; it is depending on the rest of the sentence to give it meaning. When “who/whom” appears in a dependent clause, it is important to test which is correct by replacing “who” or “whom” with the appropriate personal pronoun or rephrasing the sentence. Consider the following example:
Example: While you do not know who is the right or wrong choice, considering each one’s reputation is useful for deciding in who/whom to place your trust.
This example is a bit more complicated; however, it is more likely to resemble the complex sentences with which you write for most purposes. Look at the first instance of “who/whom” first, and mentally identify the clause (“who/whom” is right or wrong choice” is the dependent clause). In this case, “who” is correct because it is the subject of the verb. Likewise, if you were to ask “Who is the right or wrong choice?” Your answer is “he is” when supplementing a personal pronoun.
In the second appearance of “who/whom,” the rewritten clause would read “in who/whom to place your trust.” “Whom” is correct because it is the object that is affected by the verb (the placing of your trust). Similarly, your answer is “ in him” if you were to ask, “In whom am I playing my trust?”
The objective case “whom” is always used following a preposition. Taking another look at a previous example, you could make this determine “whom” is correct without doing anything else.
Example: To whom is the letter addressed? (“To” is a preposition, so since it precedes “whom,” you know that “whom” is correct.)