Who vs. whom is another grammar topic that seems to stump a lot of people, and with good reason.  After all, they both sound the same, but the way in which they are used is different. 

To get started, who and whom are pronouns.  The main difference between the two words is that who is used to refer to a clause’s subject.  Whom, on the other hand, is used to refer to a clause’s object.

Now, what is the difference between a clause’s subject and object?  Think of it this way – a subject is the person performing the action.  The object, meanwhile, is having that action performed on them.

Example:

I punched David.

I am the subject performing the action.  David is the object having the action performed on them.

If you are still unclear on the whole distinction between subject and object, think of this sweet mnemonic reminder.  If I told you “I love you,” it means that you are the object of my affection.  It just so happens that “you” is the object of the sentence as well.  It may sound corny, but it might help you remember the difference between subject and object.

Using Who

Use who when you are asking something about or referring to a sentence’s subject.  In reference to the example above, here is how you would use who:

Example:

Who punched David?

There you are asking about the subject, the person who performed the action against David.

Using Whom

Use whom when you are talking about the object of the sentence.  In reference to the first example in this article, here is how you would use whom:

Example:

Whom did you punch?

As you can see, a question is being asked about the object.