It is a common question about English rules and usage: who vs. whom. When do you use whom and who?

Who vs. Whom – know when to use which pronoun

Many native speakers do not know the usage difference between who vs. whom:

Both who and whom are pronouns. Who is the subject pronoun, in the same way as ‘he, she, they.’

Who is used when it is the subject of a verb. Example:

Joe built a house.

Joe is the subject of the verb ‘to build.’

Joe loves Mary

Joe is the subject of the verb ‘love’

Whom is an object pronoun, in the same way as ‘him, her, them.’ Example:

Mary is the object of Joe’s affection.

Subject        Verb            Object

Joe                loves            Mary

Who              loves            Mary?

Joe                loves            whom?

Simple rule: If you can substitute ‘she, he or they’, use ‘who.’  If you can substitute ‘her, him or them,’ use ‘whom.’

We can use ‘whom’ as the object of a verb, but it is very formal and not often used in spoken English.

Formal English:      Whom did you see?

Informal  English:  Who did you see?

In formal English, whom is used directly after a preposition:

With whom did you play?

In informal conversational English, it is more usual to ask :

Who did you play with

Examples:

Who drove the car?

(Who is the subject of the verb to drive.)

Sally gave her doll to who?

(Sally is the subject of to give, but who is not the subject of any verb. Therefore, you cannot use who. It should be whom. This is like saying Sally gave her doll to she.)

Understanding the context in which either word is used can help distinguish where you use who vs. whom.