The lovely wife and I were watching an old movie recently, and one of the characters answered the phone and said, “Who should I say is calling?” and my wife said, “There’s a wordo for you. She should have said, ‘Whom should I say.’” I couldn’t argue with her (not that I ever do anyway). I had just heard a perfect Type A Wordo. (If this is your first Wordo Alert, there’s a definition of wordo at the end of this article.). Trouble was that the mistake wasn’t made in the movie. It was made by my wife.

When to use who and when to use whom is probably one of the most confusing grammar problems around. Well, listen up, because I’m about to give you the solution (you wish!), or, at least, I can show you how to be right about 80% of the time, anyway.

To start with, who and whom are both types of pronouns normally used as a substitute for a noun. Where the confusion comes in is that there are different kinds of pronouns. They can be subjective, or they can be objective. (If your eyes are starting to glaze over, don’t stop reading. You don’t need to know the technical definitions to use the words right. I just need to use them to explain.) Anyway, who is a pronoun that’s used in place of the subject of a sentence. For example, “Who shows up first wins,” is an example of using who correctly. Whom is a pronoun that’s used in place of the person that something is done to (or, as we used to say back when I was in school, the person who is the object of the action). For example, in, “Whom did they give the prize to?” whom is used correctly because it’s the object of gave—or the person who got the prize.

Without all the grammar, think of who as being used in place of the person that. (It’s not real good grammar, but it’s easy to remember.) “Who works hardest earns most,” is the same as, “The person that works hardest earns most.” We’re talking about the subject of the sentence—the person who does the earning. Then think of whom as being used in the place of what person, so, “Jill gave the box to whom?” is the same as, “Jill gave the box to what person?” because this time we’re talking about the person who got the box.

Still not very clear, right? OK, so, how do you know which one to use when? Well, there’s rules of grammar, and then there’s tricks of the trade. The rule is you use who as the subject of a statement, and you use whom as the object of an action. And, you always use whom with prepositions (words that show some kind of relationship such as to, for, from, about, of, and by). And, you never use whom with a “being” verb like is and are.

Them’s the rules. Personally, I find the tricks easier to remember. There’s two: the sound trick and the substitution trick. If your sentence is a statement like the one I used before, “Who shows up first wins,” you can usually use the sound trick. Just use who and whom both to see which one sounds right. ”Whom shows up first wins,” doesn’t sound right, and it isn’t. It’s the same with, “He’s the guy who calls the shots,” or “He’s the guy whom calls the shots.” Whom doesn’t sound right. And it’s not.

It’s not as easy, though, when you write a question. “Who did you call?” and “Whom did you call?” might both sound OK to different people. That’s where the substitution trick comes in. If you write a question and use whom, just turn the question into a statement and see what pronoun you can substitute for whom. “Whom did you call?” becomes, “You called whom.” Now, which would you substitute in place of whom, her or she? “You called she,” isn’t good grammar, and it doesn’t sound right either, so you’d use her, which is correct.

How about, “Whom shall I say is calling?” As a statement, it becomes, “I shall say whom is calling.” Then you do the substitution trick with he and him. You get either, “I shall say he is calling,” or “I shall say him is calling.” “Him is calling” isn’t good grammar (and it doesn’t sound right), so you use he. And, he is correct. It might seem like you should write, “Whom did you say was coming?” or, “Whom shall I say is calling?” because we’ve heard it used that way by people who are supposed to be sophisticated and educated. But, if you do the substitution trick, you discover that they’re wrong because you can’t use whom with a verb like is or are. So, even if you’re the butler to an English lord, you still better ask, “Who shall I say is calling?” if you want to be grammatical.

But, let’s get real, here. I’ve been talking about strictly correct, grammatical usage. What about when you’re being casual or colloquial? A whole different story. Whether you write, “Whom are you talking about?” or “About whom are you talking?” it sounds very formal. In everyday use, there’s nothing wrong with, “Who are you talking about?” If you do much reading, you find out that writers as far back as, and including, Shakespeare often switched these words. So, the way things are being written these days, and because it’s so difficult to keep the rules straight, I recommend this: Unless you’ve got a really good reason to use whom, you’re generally safer if you use who in most situations.

wordo (wûrd·ō) n. Related to a typo but without a spelling or typographical error. Results from a choice of the wrong word from among similar or related words.
Type A: a choice of the wrong form of related words, e.g., its vs. it’s and their vs. there.
Type B: a wrong choice from among homophones, e.g., site vs. sight and principal vs. principle.
Type C: a wrong choice between words with similar or overlapping meanings, e.g. strategy vs. tactics and aggravate vs. annoy.
[poss. British English ]