By the end of this lesson, you’ll know exactly how to handle who vs whom , whether you’re writing a professional email or having a casual conversation. You’ll have one simple test that works every time, a clear set of real examples, and an honest sense of when the formal rule actually matters and when it doesn’t.
Most people deal with this one of two ways: they avoid “whom” entirely, or they second-guess every sentence it appears in. Both are exhausting. The truth is that who vs. whom sounds complicated but sits on top of one clean, testable rule. Once you see it, the confusion disappears. At Your Daily American, this is exactly the kind of grammar pattern we build lessons around, not abstract rules to memorize, but logic you can run in real time.
The actual difference between who and whom (in plain English)
Who is the doer. Whom is the receiver. That’s the entire rule. Everything else is just applying it.
“Who” is a subject pronoun, meaning it stands in for he, she, or they, the person doing the action. “Whom” is an object pronoun, meaning it stands in for him, her, or them: the person receiving the action, or the person appearing after a preposition like to, with, for, or from.
Compare these two: “She won the award” gives you the person who won. “I called him” gives you the person whom I called. Same person, different grammatical role, different pronoun.
This trips up a lot of ESL learners for a specific reason. In many languages, including Spanish, Portuguese, and Mandarin, the subject/object distinction is carried by word order or verb forms, not by separate pronoun forms. The idea that two different words mark two different grammatical roles is easy to miss. Add to that the fact that “whom” sounds formal, and many learners treat it as a fancy optional word rather than a grammatically distinct one. Rather than over-correcting by using “whom” in subject position because it sounds more educated, learners may also default to “who” in all contexts, both patterns are worth watching for. That’s the one mistake to avoid.
Who vs. Whom: The he/him substitution test
Here’s the test, four steps, and it works every time.
- Isolate the clause or question containing who/whom.
- Mentally rearrange it into a normal statement.
- Try replacing the pronoun with he, she, or they. If that fits, use who.
- Try replacing with him, her, or them. If that fits, use whom.
The memory anchor: both him and whom end in -m, and that shared ending is your signal. Keep it in the back of your mind whenever you’re not sure which way to go.
Applying the test to questions
Questions are tricky because the word order is inverted, and that’s exactly why the test helps. It flips the sentence back into a statement so the pronoun’s job becomes obvious. Word order in questions hides the pronoun’s grammatical role; restating as a normal sentence reveals it instantly.
- “Who/whom called you?” → Rearrange: “He called you.” → He fits → Who called you? ✓
- “Who/whom did you call?” → Rearrange: “You called him.” → Him fits → Whom did you call? ✓
Applying the test to relative clauses
This is where most learners go wrong. They track the main clause instead of the relative clause. The rule is: look only at the clause introduced by who/whom, not the whole sentence.
- “The manager who/whom hired me is great.” → Clause: “She hired me.” → She fits → who ✓
- “The manager who/whom I hired is great.” → Clause: “I hired her.” → Her fits → whom ✓
The manager is the same person in both sentences. The pronoun changes because the role changes: doer in the first, receiver in the second.
The ESL-specific challenge here: it’s easy to focus on the main clause (“I don’t know”) and lose track of the relative clause. Always test who/whom against the smaller clause it introduces. If you’re studying for exams or want exam-specific guidance, check out IELTS IDP’s Grammar 101: Who vs Whom for a focused explanation.
Who vs. Whom: 12 real examples
Here are 12 examples drawn from the three contexts where this confusion surfaces most often: questions, relative clauses, and prepositional phrases.
In everyday questions
- “Who is calling?” (He is calling → subject)
- “Whom did you contact?” (You contacted him → object)
- “Who made this?” (She made this → subject)
- “Whom should I ask?” (I should ask him → object)
One honest note: in casual spoken American English, “Who did you call?” and “Who should I ask?” are widely used and completely accepted. You won’t sound wrong for using “who” in everyday conversation, even when the grammar technically calls for “whom.” More on this in the next section. For more on casual phrasing and idioms, see Common American Expressions Every English Learner Should Know, Your Daily American.
In relative clauses
- “The person who helped me was very patient.” (She helped me → subject)
- “The person whom they promoted works in accounting.” (They promoted her → object)
- “I don’t know who is responsible for this.” (She is responsible → subject of embedded clause)
- “I don’t know whom they hired.” (They hired him → object)
The ESL-specific challenge here: it’s easy to focus on the main clause (“I don’t know”) and lose track of the relative clause. Always test who/whom against the smaller clause it introduces.
After prepositions
- “To whom should I send this?” (formal standard)
- “The colleague with whom I work is from Texas.” (formal) → casual version: “The colleague who I work with is from Texas.”
- “To whom it may concern” (fixed formal phrase)
- “From whom did you receive this?” (formal) → casual: “Who did you get this from?”
In formal written English, a pronoun immediately following a preposition traditionally takes the object form, whom . In casual speech, moving the preposition to the end of the sentence (“who did you get this from?”) is standard American English and sounds completely natural. Grammarly also explains this distinction in its who vs whom guide.
When “whom” is the stronger choice in formal American English
Register is the deciding factor here. In professional emails, cover letters, or any written communication to a client or senior colleague, “whom” after a preposition signals precision and care. In formal contexts, omitting “whom” can sometimes undermine the tone or perceived precision of your writing, though rephrasing is always a valid option when the correct form sounds stiff.
The preposition rule in professional writing: after prepositions, use “whom” in formal contexts. Merriam-Webster and many style references support this guidance; AP style and other guides sometimes prioritize natural phrasing and may favor “who” in certain constructions. For more on AP conventions, see the Purdue OWL AP style guide. The most common fixed phrases you’ll see in business correspondence are:
- “To whom it may concern”
- “With whom I’ve collaborated on this project”
- “For whom the proposal was prepared”
- “From whom we received the original request”
Here’s how register plays out in a real email opening. Formal version: “Please direct this to whoever is handling the Reston account.” Casual version: “Can you pass this along to whoever is handling the Reston account?” Apply the test to the embedded clause: “They are handling the account”, they fits, so the subject form whoever is correct in both versions. The embedded pronoun is the subject of its own clause, which overrides the preposition preceding it. Choose your level of formality based on your audience and the tone you want to set.
When “who” is completely fine (and when to just rephrase)
Here’s the honest reality of modern American English: in everyday speech, most Americans use “who” even in object position. “Who did you talk to?” is standard conversational English. Merriam-Webster itself notes that “whom” can sound “fussy and unnatural” in regular conversation and that in many constructions, using “who” instead is perfectly standard.
Using “who” in casual speech, text messages, or informal emails doesn’t mark you as making a grammar error. It marks you as a natural speaker. The goal is fluency, not performing formality in contexts where nobody expects it. Also check Word Stress in American English: A Complete Guide, Your Daily American to refine your spoken emphasis.
And if a sentence sounds stiff with “whom” but you know it’s technically required, rephrase it. Native speakers do this constantly, and it’s a legitimate writing skill, not a workaround.
- Awkward: “Whom are you going with?”
- Better: “Who are you going with?” or “Who’s going with you?”
Rephrasing isn’t a shortcut, it’s a deliberate writing decision. Use “whom” in formal writing and after prepositions; use “who” in casual speech and informal writing; rephrase when either option sounds off.
Try it yourself: four quick practice sentences
Apply the he/him substitution test to each sentence below. Choose who or whom, then check your answers. For extra practice exercises and explanations, you can also consult Scribendi’s who vs whom article.
- “Give this to (who/whom) you trust most.”
- “(Who/whom) did the team choose as the new lead?”
- “The client (who/whom) we met yesterday signed the contract.”
- “She’s the one (who/whom) always arrives early.”
Answers:
- Whom (you trust them → him fits → whom)
- Whom (the team chose him → him fits → whom)
- Whom (we met her → her fits → whom)
- Who (she always arrives early → she fits → who)
You now have a tool you can run in seconds. Every time the who vs whom question comes up, stop, rearrange the clause into a statement, and swap in he or him . The right pronoun becomes obvious immediately. That’s the whole system, straightforward, testable, and built to stick. For more lessons and grammar guides, visit Your Daily American.
