Direct comparison
Who vs whom
"Who" is the subject form — the one doing the action; "whom" is the object form — the one receiving it.
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Side-by-side comparison
| Dimension | Who | Whom |
|---|---|---|
| Grammatical role | Subject — does the action. | Object — receives the action. |
| The he/him test | Replaceable with "he" or "she". | Replaceable with "him" or "her". |
| After a preposition | Not used directly after to, for, with, etc. | Used after a preposition (to whom, for whom, with whom). |
| Example (question) | Who is calling? | Whom did you call? |
| Example (relative clause) | The author who wrote the report. | The author whom we cited. |
| Memory aid | Pairs with he — neither ends in m. | Pairs with him — both end in m. |
| Register / formality | Standard in all contexts, formal and informal. | Mainly formal writing; often replaced by who in speech. |
| Position in sentence | Typically before the verb (the doer). | Typically after the verb or preposition (the receiver). |
| Common error | Using whom as the subject ("whom is at the door"). | Using who after a preposition ("to who it concerns"). |
The he/him test, and when whom is fading
To choose between who and whom, rephrase the clause and answer it with he or him. "___ wrote the paper?" → "He wrote it", so it is who. "You spoke to ___?" → "You spoke to him", so it is whom. Both whom and him end in m, which is the trick. Whom is strictly correct as the object of a verb or preposition, but in everyday and even much formal writing it is increasingly replaced by who, especially at the start of a question ("Who did you call?"). Whom survives most reliably right after a preposition — "to whom", "for whom", "with whom" — where dropping it sounds noticeably wrong. In academic prose, using whom correctly still signals careful writing.
Common questions
FAQ
What is the simplest test for who versus whom?+
Answer the question or clause with he or him. If the natural answer is "he" (or she), use who, because both are subjects. If the natural answer is "him" (or her), use whom, because both are objects and both whom and him end in the letter m. For example, "Whom did you see?" answers as "I saw him", so whom is correct.
Is whom becoming outdated?+
In informal speech and writing, whom is often replaced by who, and few readers object — "Who did you invite?" is widely accepted. However, whom remains standard in formal and academic writing, and it is still expected directly after a preposition, as in "to whom it may concern". Knowing the rule lets you choose deliberately rather than by accident.
When must I use whom after a preposition?+
When the pronoun is the object of a preposition, formal usage calls for whom: "to whom", "for whom", "of whom", "with whom". So "the colleague with whom I collaborated" is the careful form. In casual English the preposition often moves to the end and who is used ("the colleague I collaborated with"), which is acceptable but less formal.
Going deeper
