Who vs Whom — Subject or Object Pronoun?

Q: How do I use who and whom in relative clauses?

In a relative clause, the choice depends on the function within that clause. If the relative pronoun is the subject of its clause, use who: She is the teacher who inspired me. If it is the object, use whom: She is the teacher whom I admire most. Apply the he/him test to the relative clause itself.

Q: Is "whoever" or "whomever" correct?

The same subject/object rule applies. Whoever is a subject pronoun: Give it to whoever wants it (whoever = subject of wants). Whomever is an object pronoun: Invite whomever you like (whomever = object of invite). In informal English, whoever is used for both.

Grammar B1–C1 6 min read Updated 9 June 2026

Quick Answer

Who is a subject pronoun (who did this? — he did it). Whom is an object pronoun (to whom did you speak? — I spoke to him). Tip: substitute he/him — if him fits, use whom; if he fits, use who.

The choice between who and whom trips up even advanced English learners. The logic is the same as the difference between he and him, or she and her: subject versus object. Once you know the test, the answer is always clear.

The He/Him Substitution Test

The easiest way to decide between who and whom is the he/him test:

If you can replace the word with he, she, or they (subject pronouns), use who.
If you can replace the word with him, her, or them (object pronouns), use whom.

Memory Trick

whom ends in m, and so does him. If him fits the answer, use whom.

Using “Who”

Who functions as a subject — it is the one performing the action.

Who called last night? → He called. (he = subject → who)

The person who wrote this book is brilliant. → She wrote it.

Who is responsible for this? → She is responsible.

Using “Whom”

Whom functions as an object — it receives the action or follows a preposition.

To whom did you speak? → I spoke to him. (him = object → whom)

Whom did you invite? → I invited her. (her = object → whom)

The candidate whom we selected performed well.

Who vs Whom in Relative Clauses

In relative clauses, the choice of who or whom depends on the function of the pronoun within the relative clause itself — not in the main clause.

She is the teacher who inspired me most. (who = subject of "inspired")

She is the teacher whom I admire most. (whom = object of "admire")

The man who runs the company is very experienced. (who = subject of "runs")

The man whom the company hired is very experienced. (whom = object of "hired")

Whom After Prepositions

After a preposition, always use whom (never who). This is one of the clearest cases where whom is required:

To whom it may concern.

With whom are you working?

The director, about whom we spoke, is arriving today.

For whom was this message intended?

Note

In informal speech and writing, it is increasingly common to end sentences with the preposition and use who: Who did you speak to? Who are you working with? These are acceptable in everyday contexts but whom is expected in formal writing.

Comparison Table

Function	Pronoun type	Use	Test
Subject	he / she / they	who	He called → who called?
Object	him / her / them	whom	I invited him → whom did I invite?
After preposition	him / her / them	whom	To him → to whom

Is It OK to Use “Who” for Everything?

In informal spoken English, using who where whom is grammatically required is extremely common and generally accepted. However, in formal writing, academic English, business correspondence, and English exams, the correct use of whom is expected and will be noticed if it is wrong.

Frequently Asked Questions

What is the difference between who and whom?

Who is a subject pronoun, used when the word is the subject of a verb — the person performing the action: Who wrote this? — He wrote it. Whom is an object pronoun, used when the word receives the action or follows a preposition: Whom did you see? — I saw him. The he/him substitution test is the easiest way to decide: if him fits the answer, use whom.

What is the he/him test for who and whom?

Rearrange the sentence as a statement and substitute he or him. If he fits, use who. If him fits, use whom. Example: Who/Whom did you invite? → You invited him (not he). Him fits, so use whom: Whom did you invite? Example 2: Who/Whom called? → He called (not him). He fits, so use who: Who called? This test works reliably in nearly all cases.

Should I always use "whom" after a preposition?

In formal writing, yes. After a preposition such as to, for, with, about, by, of, you should use whom: To whom did you speak? With whom are you working? For whom was this intended? In informal speech, the preposition is often moved to the end and who is used instead: Who did you speak to? Who are you working with? Both are widely understood, but whom is required in formal contexts.

Is it acceptable to use "who" instead of "whom" in conversation?

Yes, in informal conversation it is very common and generally accepted to use who in all positions: Who did you see? Who did you speak to? This is standard in everyday spoken English. However, in formal writing, academic papers, professional emails, and English exams (IELTS, CAE, CPE), the grammatically correct whom is expected when the word functions as an object or follows a preposition.

How do I use who and whom in relative clauses?

In a relative clause, the choice depends on the function of who/whom within that clause. If the relative pronoun is the subject of its clause, use who: She is the teacher who inspired me (who = subject of inspired). If it is the object, use whom: She is the teacher whom I admire most (whom = object of admire). Apply the he/him test to the relative clause itself: she inspired him → him → whom.

What is "to whom it may concern"?

"To whom it may concern" is a formal salutation used in letters or emails when the recipient is unknown. Whom is correct here because it follows the preposition to (to him, not to he). It is a fixed expression used at the start of formal correspondence when you do not know the name of the person you are writing to. In modern practice, alternatives like "Dear Sir/Madam" or a specific job title are often preferred.

Can "whom" be used as a subject?

No. Whom is always an object pronoun and cannot function as a grammatical subject. Using whom as a subject is an error: "Whom is responsible?" is incorrect — use "Who is responsible?" A common hypercorrection is using whom in an attempt to sound formal when who is actually required. The he/him test will tell you: if you can answer with he/she/they, use who.

Is "whoever" or "whomever" correct?

The same subject/object rule applies to whoever and whomever. Whoever is a subject pronoun: Give it to whoever wants it (whoever = subject of wants). Whomever is an object pronoun: Invite whomever you like (whomever = object of invite). The he/him test works here too: He wants it → whoever. You like him → whomever. In informal English, whoever is used for both.

Does "whom" sound old-fashioned?

Whom is used less frequently in informal spoken English than it used to be, and some linguists suggest it is declining. However, it remains standard and expected in formal writing, business English, academic English, and formal exams. Using it correctly shows grammatical precision. In casual conversation, using who for both subject and object is common and understood. For professional or academic writing, learning to use whom correctly is worthwhile.

How does "who" differ from "that" as a relative pronoun?

Both who and that can introduce relative clauses referring to people, but who is generally preferred for people: the teacher who helped me (preferred) vs the teacher that helped me (acceptable but less common with people). That is more commonly used for things: the book that I read, the house that she bought. Whom is used as the object form: the teacher whom I admire. In defining relative clauses, the pronoun can often be omitted: the teacher I admire most.