Does anyone really know the difference between who and whom? It seems these poor words have gotten a bad rap for being the most confusing and most  misused pair of words in the world of grammar. Luckily, there are a couple of tricks to help you remember which is which.

The nitty-gritty:
Who is used to refer to the subject of a sentence (the person or thing that is doing something).
Whom is used to refer to the object of a sentence (the person or thing that is having something done to it).

Can whoever ate my brownies please replace them? (who, the person who ate the brownies, is the subject and the brownie is the object)
Who broke my bicycle? (who, the person who broke the bicycle, is the subject and the bicycle is the object)

Melissa talks about grammar to whomever she can. (Melissa, doing the talking, is the subject and whom, the people being forced to listen to lectures about grammar, is the object)
Whom did you kiss? (You, the person doing the kissing, are the subject and whom, the person getting kissed, is the object)

Here’s a handy trick that might help you remember the difference: Rearrange the sentence in your head, replacing who/whom with he/him. If he makes the most sense, then the word should be who, if him makes the most sense, then the word is whom. (As tricky as the who/whom thing is, deciding between he/him is easy.)

Who = he
Whom = him

Who broke my bicycle =  Him broke my bicycle He broke my bicycle
Whom did you kiss? = Did you kiss him? Did you kiss he?

Another bit of advice from The New York Times’s William Safire:

“The best rule for dealing with who vs. whom is this: Whenever whom is required, recast the sentence. This keeps a huge section of the hard disk of your mind available for baseball averages.”

It seems like a pretty simple concept, but I’ll be honest: it took me years to finally grasp the difference, and I still second-guess myself sometimes, so don’t beat yourself up if you haven’t mastered it yet. And luckily, since there’s so much doubt and confusion surrounding the terms, it’s unlikely that someone will correct you if you use the wrong word in everyday conversation. (Similarly, try not to correct someone for using the wrong word unless it’s used in a piece of writing that is going to be critiqued: you don’t want to be that person.)

A bit of who/whom comedy from The Office: