Use who when the word is the subject of a verb (the person doing something). Use whom when it’s the object (the person something is done to, or the person after a preposition). Who works like he or she; whom works like him or her.
- Who called you? (He called you.)
- Whom did you call? (You called him.)
The fastest way to decide is the he/him test, which we’ll walk through below. And here’s some good news for everyday American English: in casual speech and informal writing, who is widely accepted almost everywhere. Whom still matters in formal writing, and that’s where getting it right makes you look sharp.
Subject vs. Object: The Core Rule
Every clause has a subject (who’s acting) and often an object (who’s receiving the action). Who and whom follow the same pattern as the pronouns you already use without thinking.
| Role | Use | Same as | Example |
|---|---|---|---|
| Subject (does the action) | who | he, she, they | Who wrote this report? |
| Object of a verb | whom | him, her, them | Whom did the board hire? |
| Object of a preposition | whom | him, her, them | To whom should I send it? |
You’d never say “Him wrote the report” or “The board hired he.” The same instinct, applied with a quick test, solves who vs. whom.
The He/Him Test
Here’s how to run it:
- Take the part of the sentence with who or whom and turn it into a statement.
- Replace who/whom with he or him.
- If he sounds right, use who. If him sounds right, use whom.
Memory trick: Him and whom both end in m. If him fits, whom fits.
Let’s try it:
- (Who/Whom) is coming to dinner? → He is coming to dinner. → Who is coming to dinner?
- (Who/Whom) should we invite? → We should invite him. → Whom should we invite?
- The woman (who/whom) I met yesterday is a pilot. → I met her yesterday. → The woman whom I met yesterday is a pilot.
- The man (who/whom) fixed the sink was fast. → He fixed the sink. → The man who fixed the sink was fast.
With questions, you’ll often need to rearrange the words before testing. “Whom did you see?” becomes “You saw him.” Take a second to flip it around and the answer is usually obvious.
Who and Whom After Prepositions
When the word comes right after a preposition (to, for, with, from, by, about, of), it’s an object, so formal English uses whom.
- To whom it may concern
- For whom the bell tolls
- With whom did you travel?
- The client, from whom we received the complaint, has called back.
In casual speech, Americans usually move the preposition to the end and use who: “Who did you travel with?” That’s normal, natural English. What sounds odd is mixing the two styles: “With who did you travel?” If the preposition comes first, follow it with whom.
| ❌ Avoid | ✅ Use (formal) | ✅ Use (casual) |
|---|---|---|
| To who should I address this? | To whom should I address this? | Who should I address this to? |
| With who are you meeting? | With whom are you meeting? | Who are you meeting with? |
If you’re unsure whether ending a sentence with a preposition is allowed, it is. Our grammar rules guide explains why that old “rule” doesn’t hold up.
Whoever vs. Whomever
The same subject/object logic applies to whoever and whomever, but there’s a twist: what matters is the word’s role inside its own clause, not its role in the whole sentence.
- Give the extra tickets to whoever needs them.
At first glance, to looks like it calls for whomever. But the object of to is the whole clause whoever needs them. Inside that clause, whoever is the subject of needs (he needs them). So whoever is correct.
Compare:
- Give the tickets to whomever you choose. (You choose him. Whomever is the object of choose.)
- Whoever finishes first wins a prize. (He finishes first.)
- We’ll hire whomever the committee recommends. (The committee recommends him.)
Quick rule: Ignore the words outside the clause. Find the verb that whoever/whomever belongs to, then run the he/him test on that clause alone.
When “Who” Is Perfectly Fine
In everyday American English, whom has been fading from casual use for a long time. Merriam-Webster notes that who is commonly used as an object in speech and informal writing, and most listeners won’t notice or care. “Who did you see at the party?” is standard conversational English.
You can comfortably use who in:
- Conversation and casual email
- Text messages and social media
- Informal blog posts and dialogue in fiction
If you write “Whom are you texting?” to a friend, it may come across as stiff or joking. Matching your tone to the setting matters as much as the rule itself. (For more on casual registers, see our guide to text slang.)
When “Whom” Still Matters
In formal writing, editors and style guides such as The Chicago Manual of Style and the AP Stylebook still distinguish who from whom. Use the traditional rule in:
- Academic papers and research writing
- Legal, business, and official documents
- Cover letters, grant proposals, and formal correspondence
- Published articles that follow a style guide
If you’re unsure whether a document is formal enough, a good shortcut is this: if you’d avoid contractions in it, use whom where it belongs. And if whom sounds awkward even when it’s correct, you can usually rewrite: “Whom did you contact?” can become “Which person did you contact?”
Common Traps
“Whom I think is” (wrong)
This is the most common mistake made by people trying hard to be correct. Phrases like I think, we believe, or they said get dropped into the middle of a clause, and they make the pronoun look like an object. They aren’t.
- ❌ The candidate whom I think is best qualified…
- ✅ The candidate who I think is best qualified…
Remove the inserted phrase and test: The candidate who I think is best qualified. → He is best qualified. So it’s who.
| ❌ Avoid | ✅ Use | Test |
|---|---|---|
| Whom shall I say is calling? | Who shall I say is calling? | He is calling. |
| The person whom we believe stole it | The person who we believe stole it | He stole it. |
| Whomever wins will get a bonus. | Whoever wins will get a bonus. | He wins. |
| Who did they promote? (formal writing) | Whom did they promote? | They promoted him. |
Overcorrecting with “whom”
Using whom where who belongs sounds more wrong to many readers than the reverse. If you’re unsure in a formal sentence, run the test rather than guessing whom to sound polished.
Practice: Who or Whom?
Choose who, whom, whoever, or whomever for formal writing.
- ______ left the lights on in the conference room?
- To ______ did you give the keys?
- The doctor ______ treated my sister is retiring.
- The applicant ______ we interviewed on Monday accepted the offer.
- Please send the file to ______ is managing the account.
- The speaker ______ I think will impress you most goes on last.
Answer Key
- Who (He left the lights on.)
- whom (after the preposition to; you gave him the keys)
- who (He treated my sister.)
- whom (We interviewed him.)
- whoever (He is managing the account; the whole clause is the object of to.)
- who (Drop “I think”: He will impress you most.)
Want more pairs like this? Try affect vs. effect or lay vs. lie, and keep our tricky words guide bookmarked.
The Bottom Line
Who is for subjects (like he), and whom is for objects (like him). Run the he/him test, use whom right after a preposition, and judge whoever/whomever by its own clause. In casual American English, who is fine almost everywhere. In formal writing, the distinction still counts, and it’s one of the easiest ways to show careful work. That’s the kind of practical rule we focus on at GrammarVista.com USA.