Who vs. Whom: When It Actually Matters and When It Doesn't
Formal writing still uses 'whom', but informal writing has mostly dropped it. Here is how to decide per context.
A Rule That Is Slowly Fading
The difference between who and whom comes down to subject versus object, the same split that separates 'he' from 'him'. 'Who' acts as the subject of a clause, the one doing something. 'Whom' acts as the object, the one receiving the action. The grammar is straightforward, but usage is shifting fast.
In speech and casual writing, 'whom' has mostly disappeared. People say 'Who did you call?' even though 'whom' is technically correct, and almost no one blinks. In formal writing, academic work, and careful business prose, 'whom' still belongs. Knowing the rule lets you turn it on when the context demands polish and drop it when it would sound stiff.
Who vs. Whom by Function
| Role | Pronoun | Quick test | Example |
|---|---|---|---|
| Subject | who | Swap with 'he' or 'she' | Who left the door open? |
| Object | whom | Swap with 'him' or 'her' | Whom did you invite? |
| After a preposition | whom | Always the object form | To whom should I send this? |
| Casual speech | who | Acceptable in most contexts | Who are you calling? |
The Substitution Test That Almost Always Works
If you can answer the question with 'he' or 'she', the correct word is 'who'. If the natural answer is 'him' or 'her', use 'whom'. The 'm' on him and them matches the 'm' on whom, which makes the test easy to remember. Ask yourself 'did you call him?' and the 'him' tells you the question was 'whom did you call?'
The test holds even in complex sentences. 'I spoke with a manager who I trust' becomes 'I trust him', so the correct formal version is 'whom I trust'. The reason people write 'who' here is that the whole clause sits inside another sentence, which muddies the role. The substitution cuts through the structure and gives you the answer.
When the pronoun follows a preposition like to, for, with, or about, it takes the object form. 'With whom', 'for whom', and 'about whom' are not optional in formal writing. If you wrote 'with who', a careful editor would flag it.
When Whom Still Matters
Formal contexts are where 'whom' earns its place. Academic papers, legal documents, official correspondence, and cover letters all benefit from the object form. In those settings, using 'who' for an object can read as careless, the kind of slip a reviewer notices even if they do not point it out.
In journalism and business writing, usage has loosened. Major outlets often use 'who' for objects in headlines and casual pieces, reserving 'whom' for quoted speech and formal columns. The Chicago Manual of Style preserves the traditional distinction, while the AP Stylebook allows more flexibility. Match the level of your publication and your audience's expectations.
A Practical Way to Decide
- Use 'whom' in academic, legal, and official writing without exception
- Use 'whom' after a preposition in any context above casual speech
- Default to 'who' in dialogue, social posts, and informal email
- Run the him-or-her test whenever you are unsure, even mid-sentence
Choosing Who or Whom in Five Steps
- 1Locate the clause
Find the clause where the pronoun lives, since its role is decided inside that clause, not by the surrounding sentence.
- 2Identify its role
Determine whether the pronoun is the subject doing the action or the object receiving it.
- 3Run the substitution
Replace the pronoun with he or him. If he fits, use who. If him fits, use whom.
- 4Check the register
Decide whether the context is formal enough to warrant whom, or casual enough to let who slide.
- 5Read it aloud
If 'whom' sounds stuffy to your intended reader and the setting is informal, switch to 'who' without guilt.
The Rule in Brief
Who does, whom receives. Use the form that matches the role, then decide whether your audience wants the formal version or the natural one.
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