Short answer
Who is generally used for the subject of a verb, while whom is used for the object of a verb or preposition. In contemporary US English, whom is rare in speech and often replaced by who, except in formal writing. 1 2 3
Both are pronouns related to people, but who functions as a subject and whom as an object; in practice, who often replaces whom in informal contexts.
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At a glance
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| Question | who | whom |
|---|---|---|
| Typical grammatical role | Subject of verb | Object of verb/preposition |
| Common in speech | Yes | Rare, sounds formal |
The table summarizes the stated definitions and scope. 1 2 3
What each thing is
Who. Who is a pronoun used to refer to the subject of a verb, typically introducing questions or relative clauses about people or sometimes animals or groups. 1 2
Whom. Whom is the objective case of who, used as a pronoun to refer to the object of a verb or preposition, especially in formal or traditional contexts. 1 3
Key differences
The main distinction is grammatical role: who is used as a subject, while whom is used as an object. This difference is most noticeable in questions and relative clauses. 1 2 3
How to tell them apart
A practical test is to substitute he/she for who and him/her for whom. However, this method can be tricky in complex sentences, and actual usage often ignores the distinction in informal settings. 1
Where they overlap
Who and whom do not overlap in strict grammar, but in everyday US English, who is frequently used in both subject and object positions, making whom largely optional outside formal writing. 1 2 3
Edge cases
Immediately after a fronted preposition, ‘whom’ remains standard in formal prose: ‘To whom did you speak?’ Everyday speech often moves the preposition and uses ‘who’: ‘Who did you speak to?’ The two constructions differ in register, not in who is being asked about. 1 3
Why the distinction exists
The difference reflects English case marking: who is nominative (subject), whom is objective (object). This distinction is a holdover from older English, but has faded in everyday use. 3
Common misconceptions
A common misconception is that using whom is always required when it is technically correct. In reality, who is widely accepted in object positions except in the most formal writing. 1 2 3
Examples
Compare: “Who did you invite?” (informal, common) and “Whom did you invite?” (formal, less common). Both are understood, but only the second strictly follows traditional grammar for objects. 1 2
Sources
Sources checked October 3, 2026.
- Merriam-Webster — How to Use Who vs. Whom. Usage guide: definitions, examples and exceptions.
- Merriam-Webster — Who Definition & Meaning. Dictionary entry: definitions, usage examples and word history.
- Merriam-Webster — Whom Definition & Meaning. Dictionary entry: definitions, usage examples and word history.