Whom or Who: Which Is Correct? Rules, Examples, and Common Mistakes

Choosing between whom or who can be confusing because both words refer to people, and they sometimes appear in similar sentence structures. The main difference is grammatical: who is a subject pronoun, while whom is an object pronoun. Once you understand how subjects, objects, and prepositions work, choosing the correct word becomes much easier.

The same rule helps you decide whether to write to who or to whom, who to ask or whom to ask, and other expressions that often cause confusion. However, formal grammar and everyday English do not always sound the same. Although whom remains useful in formal writing, many English speakers use who in ordinary conversation.

This guide explains the difference between who and whom, the rules for using them, examples of correct and incorrect sentences, and practical ways to remember the right choice.

Quick Answer: Who or. Whom

Use who when the person is the subject of a verb—the person performing the action. Use whom when the person is the object of a verb or preposition in formal standard English.

Word	Grammatical role	Example
Who	Subject pronoun	Who called you?
Whom	Object pronoun	Whom did you call?
Who	Subject in a relative clause	The woman who helped me was kind.
Whom	Object in a relative clause	The woman whom I helped was kind.
To whom	Object of a preposition	To whom should I send the letter?
Who … to	Common conversational construction	Who should I send the letter to?

A simple trick can help you choose: replace who with he and whom with him. If he fits, use who. If him fits, use whom in the formal construction.

For example:

• Who opened the door? — He opened the door.
• Whom did you invite? — I invited him.
• To whom did you give the keys? — I gave the keys to him.

The rule depends on the pronoun’s grammatical role, not simply on where it appears in the sentence.

What Is the Difference Between Who and Whom?

The difference between who and whom comes down to subject and object forms. English uses different forms for some personal pronouns depending on their roles in a sentence. For example, we say he called but I called him. The distinction between who and whom follows the same principle.

What Does Who Mean?

Who is a subject pronoun used to ask about a person or identify someone. It commonly appears when the person is doing the action described by the verb.

Examples include:

• Who is waiting outside?
• Who wrote this article?
• Who wants another cup of coffee?
• The student who answered the question received a prize.
• I know who lives in that house.

In each example, who functions as the subject of its own clause. It identifies the person performing an action or being described.

Notice that who can appear in the middle of a sentence. It does not have to be the first word of a question. In “I know who called,” the word who is still the subject of called, even though the entire sentence is a statement.

What Does Whom Mean?

Whom is the object form of a pronoun. It refers to a person who receives an action or follows a preposition. It is especially common in formal writing and carefully structured questions.

Examples include:

• Whom did you invite?
• Whom should we contact?
• The manager whom I met was helpful.
• To whom did you give the documents?
• The candidate whom the committee selected accepted the position.

In the first sentence, you performs the action of inviting, and whom refers to the person receiving that action. In the final example, the committee selects the candidate, so whom functions as the object of selected.

In modern English, whom is used less often in conversation than in formal writing. In many sentences, speakers use who instead, especially when the preposition comes at the end.

Who or. Whom: A Comparison Table

Feature	Who	Whom
Pronoun form	Subjective	Objective
Main function	Subject of a clause	Object of a verb or preposition
Similar pronoun	He, she, they	Him, her, them
Example question	Who called you?	Whom did you call?
Formal preposition use	Usually not placed directly after a preposition	Common after a preposition
Everyday speech	Very common	Less common
Formal writing	Correct when used as a subject	Useful when used as an object

Remember: The position of a word does not automatically determine its grammatical role. You need to examine the clause in which it appears.

To Who or To Whom: Which Is Correct?

The question “Is it to who or to whom?” comes up frequently in formal letters, emails, questions, and everyday conversation.

In traditional formal grammar, to whom is the preferred construction because to is a preposition and whom is its object form. For example:

• Formal: To whom should I address the letter?
• Formal: To whom are you speaking?
• Formal: To whom do I refer in this report?
• Formal: To whom should I direct this question?

In informal English, speakers commonly put the preposition at the end of the sentence and use who:

• Conversational: Who should I address the letter to?
• Conversational: Who are you speaking to?
• Conversational: Who do I refer to in this report?
• Conversational: Who should I direct this question to?

Both patterns are widely understood, but they differ in tone. The versions with to whom sound more formal, while the versions with who … to generally sound more natural in conversation. Cambridge English Grammar describes whom as the object form used in formal styles and notes that some formal styles prefer placing the preposition before it.

Why Is “To Whom” Correct?

The traditional rule is based on pronouns and prepositions. In standard formal English, a preposition is normally followed by an object form:

• to him, not to he
• for her, not for she
• with them, not with they
• to whom, rather than to who

Consider this example:

To whom did you send the invitation?

You could rewrite the sentence as “I sent the invitation to him.” Because him is the object of to, whom is the traditional formal choice in the question.

Another example is the familiar formal greeting:

To whom it may concern

This expression is commonly used when the writer does not know the name of the person who will read a letter, certificate, or other document.

Is “To Who” Grammatically Correct?

The phrase to who occurs in informal English, but it is generally avoided in formal writing when the pronoun directly follows the preposition to.

For example:

Context	Example	Recommendation
Formal letter	To whom it may concern	Preferred
Academic writing	To whom should the results be submitted?	Preferred
Everyday conversation	Who should I give this to?	Natural
Formal preposition-first question	To who should I give this?	Use to whom instead

This distinction matters because grammatical correctness and everyday usage are not always identical. Many native English speakers naturally choose who in conversation, even in sentences where traditional formal grammar would favor whom.

For professional correspondence, formal applications, academic writing, and other situations where a traditional grammatical style is expected, choose to whom.

When to Use Who or Whom

The easiest way to understand when to use whom and when to use who is to identify the role the pronoun plays in its own clause.

Use Who for the Subject of a Sentence

A subject pronoun performs the action of the verb or serves as the subject being described.

Examples:

• Who broke the window?
• Who is responsible for this project?
• Who sent you the message?
• The person who called left a voicemail.
• I wonder who made this decision.

In “Who sent you the message?”, the person represented by who performs the action of sending. Therefore, who is correct.

The same principle applies to relative clauses. In “The person who called left a voicemail,” the word who is the subject of called.

Use Whom for the Object of a Verb

An object pronoun refers to the person receiving an action or affected by it.

Examples:

• Whom did the teacher praise?
• Whom did you invite to dinner?
• Whom are they interviewing?
• The person whom we hired starts Monday.
• She asked whom I had contacted.

Look at this sentence:

“Whom did the teacher praise?”

The teacher performed the action, and the person represented by whom received the praise. The formal object form is therefore appropriate.

In less formal English, you will often hear “Who did the teacher praise?” This is common usage, particularly in speech. In formal writing, whom makes the object relationship explicit.

Use Whom as the Object of a Preposition

A preposition expresses a relationship between words. Common examples include to, for, with, by, from, and about.

When a preposition appears immediately before the pronoun in formal English, use whom.

Preposition	Formal example
To	To whom did you speak?
For	For whom is this package?
With	With whom are you traveling?
By	By whom was the decision made?
From	From whom did you receive the email?
About	About whom were they talking?

The same pattern applies to relative clauses:

• The colleague to whom I sent the report replied.
• The friend with whom I traveled lives nearby.
• The person for whom I bought the gift has arrived.

These examples are grammatically appropriate in formal writing. In conversation, people often move the preposition to the end and use who: “Who did you travel with?”

Use the He/Him Test

The he/him test is a simple method for choosing the correct pronoun. Rewrite the sentence or answer the question using an ordinary personal pronoun.

• If he, she, or they fits, choose who.
• If him, her, or them fits, choose whom in the formal construction.

For example:

Question: Who called you?

Answer: He called me.

Because he fits, who is correct.

Question: Whom did you call?

Answer: I called him.

Because him fits, whom is the formal choice.

Try another example:

Question: To whom did you send the file?

Answer: I sent the file to her.

Because her is the object of to, whom fits the formal question.

The test works for most ordinary cases, but you must apply it to the correct clause. In a sentence with multiple clauses, the pronoun’s role within its own clause is what matters.

Who to or Whom to: Which Is Correct?

The choice between who to or whom to depends on how the pronoun functions in the clause. Both forms can occur in modern English, but who to is more common in everyday conversation, while whom to can sound more formal.

Consider these examples:

• I don’t know who to ask.
• I don’t know whom to ask.
• She needs to decide who to invite.
• She needs to decide whom to invite.
• We haven’t chosen who to contact yet.
• We haven’t chosen whom to contact yet.

The first version in each pair is natural in everyday English. The second uses the traditional object form and may be preferred in formal writing.

Why Is “Who to Ask” Correct?

In a sentence such as “I don’t know who to ask,” the phrase who to ask is an embedded construction. The word who is associated with the action of asking, and it identifies the person being asked.

Traditional formal grammar may favor whom because the person is the object of ask. However, modern English commonly uses who in these constructions, including in edited writing.

Compare:

Everyday English	More formal alternative
I don’t know who to ask.	I don’t know whom to ask.
Tell me who to contact.	Tell me whom to contact.
We need to choose who to invite.	We need to choose whom to invite.
She knows who to consult.	She knows whom to consult.

Neither version changes the basic meaning. Choose the wording that suits the audience, tone, and style of your writing.

Who to or Whom to Examples in Questions

The distinction becomes clearer when you compare the role of the pronoun in different clauses.

• Who should handle the complaint? — Who is the subject of should handle.
• Do you know who should handle the complaint? — Who remains the subject of should handle.
• Do you know whom the manager selected? — Whom is the object of selected in formal English.
• Do you know who the manager selected? — This is also common in modern English.

The key lesson is that a pronoun does not automatically become whom simply because it appears inside a longer sentence. Examine the verb and identify the role of the pronoun within its clause.

Can You Use Whom After a Preposition?

Yes. Using whom after a preposition is one of the clearest traditional rules for formal English.

A preposition such as to, with, for, or about can introduce a noun or pronoun that completes its meaning. When that word refers to a person, whom is the traditional object form.

Examples include:

• To whom should I send this application?
• With whom did you attend the meeting?
• For whom are you buying the flowers?
• About whom did the witness speak?
• From whom did you receive this information?

These sentences use a formal structure in which the preposition comes directly before whom.

Can a Preposition Come at the End of a Sentence?

Yes. English allows prepositions at the end of questions and clauses, especially in conversational and natural writing. This structure is sometimes called a stranded preposition.

Compare these examples:

More formal	More conversational
To whom are you speaking?	Who are you speaking to?
With whom did you travel?	Who did you travel with?
For whom is the gift intended?	Who is the gift for?
About whom were you asking?	Who were you asking about?

The conversational versions are not automatically grammatical errors. They are standard patterns in everyday English. The formal versions may be more suitable for legal documents, official letters, academic writing, or situations where a traditional style is expected.

Practical rule: If the preposition comes immediately before the pronoun, use whom in formal English. If the preposition appears at the end of a natural question, who is widely accepted.

To Which: Is It Correct Grammar?

To which is grammatically correct when which refers to a thing, choice, subject, or other non-person referent and the sentence requires the preposition to.

Examples:

• To which address should I send the package?
• The department to which I applied has contacted me.
• The question to which she referred was difficult.
• The route to which the guide directed us was closed.

In these examples, which refers to an address, department, question, or route. It does not replace whom when the referent is a person.

To Whom or. To Which

Phrase	Used for	Example
To whom	People	To whom did you give the keys?
To which	Things, choices, or specified entities	To which folder should I save the file?
To what	Questions about a thing, degree, or extent	To what extent is the claim accurate?

The choice depends on meaning and sentence structure, not merely on the preposition.

Is “To Which Extent” Correct?

The expression to what extent is generally more natural and standard when asking about the degree or limits of something.

For example:

• Preferred: To what extent did the policy affect the results?
• Less natural in most contexts: To which extent did the policy affect the results?

However, which is correct when it identifies a specific option or item: “To which extent of the project does this rule apply?” Even here, another construction may sound clearer, such as “Which part of the project does this rule apply to?”

Use to what extent for general questions about degree, influence, or scope.

How to Use Whom in a Sentence

You can use whom in a sentence when the pronoun functions as an object, especially in formal questions and writing.

Whom as the Direct Object

A direct object receives the action of a verb.

Examples:

• Whom did the director choose?
• Whom did you meet at the conference?
• The author whom I interviewed was friendly.
• The person whom we hired has extensive experience.

In “Whom did you meet?”, you perform the action of meeting. The pronoun whom identifies the person you met.

Whom as the Indirect Object

An indirect object identifies the person who receives something or benefits from an action.

Examples:

• To whom did you give the documents?
• For whom did she prepare the presentation?
• The colleague to whom I sent the invitation accepted.

An indirect object often appears with a verb such as give, send, tell, or offer. The wording of a sentence determines whether the pronoun appears directly as an object or follows a preposition.

Whom in Relative Clauses

A relative pronoun introduces a clause that provides more information about a person or thing. When the pronoun refers to a person and functions as the object of the relative clause, formal writing can use whom.

Examples:

• The applicant whom we interviewed was well prepared.
• The professor whom I contacted replied promptly.
• The client to whom we sent the proposal requested changes.

In many informal sentences, whom can be replaced by who or omitted when it is the object of a relative clause:

• Formal: The applicant whom we interviewed was well prepared.
• Informal: The applicant who we interviewed was well prepared.
• Informal: The applicant we interviewed was well prepared.

However, when the preposition appears immediately before the relative pronoun, the formal pattern keeps whom: “The client to whom we sent the proposal.”

Who and Whom in Formal and Informal Writing

The choice between who and whom is not only about grammar. It can also affect the tone of your writing.

Who and Whom in Formal Writing

In formal writing, whom can make the grammatical relationship clear and help maintain a traditional style. It is useful in:

• Official letters and applications
• Academic essays and reports
• Legal or administrative documents
• Formal interviews and questionnaires
• Professional correspondence where a formal tone is appropriate

Examples:

• To whom it may concern
• The individual whom the committee selected
• With whom should I arrange the appointment?
• The consultant to whom we referred the case has replied.

Formal writing does not require you to use whom in every sentence. Use it where it fits the grammatical structure and where the tone suits your purpose.

Who and Whom in Informal Writing

In everyday speech, people commonly use who in places where traditional formal grammar would use whom. This is especially common when a preposition appears at the end of a question.

Examples:

• Who are you talking to?
• Who did you invite?
• Who should I call?
• Who were you waiting for?

These sentences sound natural in conversation and are widely understood. You do not need to force whom into every informal question.

Is Whom Still Used in Modern English?

Yes. Whom is still used in modern English, particularly in formal writing, fixed expressions, and constructions with a preposition placed directly before it.

However, its use is less frequent in everyday conversation than who. Many speakers prefer a sentence that sounds natural rather than one that follows the traditional distinction in every case.

This does not mean the word whom is obsolete or incorrect. It remains a standard part of English grammar. The important distinction is between a formal construction and common informal usage.

Common Mistakes When Using Who and Whom

Even confident English writers sometimes confuse who and whom. Most common grammatical errors happen when writers focus on the position of the pronoun instead of its role in the clause.

Using Who After a Preposition in Formal Writing

Incorrect for traditional formal style: To who should I address the letter?

Preferred: To whom should I address the letter?

The preposition to takes an object, so whom is the traditional formal choice. In everyday conversation, “Who should I address the letter to?” is also natural.

Choosing Whom Just Because a Sentence Sounds Formal

Incorrect: Whom is responsible for this decision?

Correct: Who is responsible for this decision?

The person represented by who is the subject of is responsible. A formal tone does not change the grammatical role of the pronoun.

Confusing the Main Clause With an Embedded Clause

Correct: I know who wrote the report.

Incorrect in the intended standard construction: I know whom wrote the report.

The pronoun is the subject of wrote, even though the entire clause “who wrote the report” is the object of know. The pronoun’s grammatical role inside its own clause determines the choice.

Assuming Whom Is Always Better

Both of these are natural in modern English:

• Who did you invite?
• Whom did you invite?

The second follows the traditional object-pronoun distinction more strictly. The first is widely used in everyday speech. Choose the version that suits the context rather than automatically replacing every who with whom.

Confusing Who With Which

Use who or whom for people and which for things or choices in the relevant construction.

• Person: The colleague whom I contacted replied.
• Thing: The document which I requested arrived.
• Formal preposition: The colleague to whom I spoke was helpful.
• Formal preposition for a thing: The document to which I referred was missing.

Quick Review of Correct and Incorrect Sentences

Incorrect or less suitable in formal writing	Correct or preferred alternative
To who should I write?	To whom should I write?
Whom is calling?	Who is calling?
The person whom called me	The person who called me
To which person did you speak?	Grammatically correct, but “To whom did you speak?” is more direct
To which extent was it successful?	To what extent was it successful?
The person to who I spoke	The person to whom I spoke

Remember that some examples in the left column are not equally wrong in every context. For instance, who is common after a preposition at the end of a conversational question. The best correction depends on the full sentence and the level of formality.

Google Books Ngram Viewer: How Has Usage Changed?

The Google Books Ngram Viewer is a tool that lets you compare how frequently words and phrases appear in a large collection of published books over selected periods. You can use it to explore historical usage trends involving expressions such as to whom and to who.

Visit the Google Books Ngram Viewer to compare phrases and adjust the date range or book collection.

How to Compare “To Whom” and “To Who”

Follow these steps:

• Open the Google Books Ngram Viewer.
• Enter the phrases to whom and to who, separated by a comma.
• Select an English-language corpus and a suitable date range.
• Review the graph to compare the phrases’ relative frequency.
• If a result seems surprising, check examples in Google Books to understand the context.

The graph can help illustrate how written usage varies over time. It can also reveal differences between phrases in a particular book collection.

Does Ngram Prove Which Phrase Is Correct?

No. Frequency is not the same as grammatical correctness. A phrase may appear in published books because it occurs in dialogue, quotations, informal writing, or a particular historical context.

Google also explains that its Ngram Viewer charts word and phrase frequencies in selected book corpora, and that results can change as its datasets and processing improve. The tool is useful for studying language patterns, but it does not determine whether a sentence follows a particular grammar rule.

For that reason, use Ngram as supporting evidence about written usage, not as a replacement for grammar references.

Practical Rules for Choosing the Correct Pronoun

When you are unsure whether to use who or whom, follow these steps.

• Find the clause. Identify the verb that the pronoun is connected to.
• Identify the role. Ask whether the pronoun performs the action or receives it.
• Try the he/him test. If he fits, use who. If him fits, whom is the traditional object form.
• Check for a preposition. In formal English, use whom immediately after a preposition when referring to a person.
• Consider the tone. Everyday English often uses who where formal writing prefers whom.
• Check the meaning of which. Use which when referring to things, choices, or the relevant non-person antecedent.

The most important point is to examine the pronoun’s role in its own clause. Do not choose whom merely because the sentence is long or formal.

Who or Whom: Practice Exercises

Choose the best answer for each sentence. Where both forms are used in modern English, consider whether the sentence is intended to follow traditional formal grammar.

• ___ called you last night? (Who / Whom)
• ___ did you invite to the event? (Who / Whom)
• To ___ should I send the application? (who / whom)
• The teacher ___ helped me was very patient. (who / whom)
• The teacher ___ I thanked smiled. (who / whom)
• Do you know ___ to contact? (who / whom)
• With ___ did you attend the conference? (who / whom)
• ___ is responsible for this report? (Who / Whom)
• The client to ___ we sent the proposal replied. (who / whom)
• To ___ extent did the changes affect the results? (which / what)

Answer Key

Question	Answer	Explanation
Who called you last night?	Who	The pronoun is the subject of called.
Whom did you invite?	Whom	The pronoun is the object of invite in formal grammar.
To whom should I send the application?	Whom	It follows the preposition to.
The teacher who helped me	Who	The pronoun is the subject of helped.
The teacher whom I thanked	Whom	The pronoun is the object of thanked in formal grammar.
Do you know who to contact?	Who	Common modern usage; whom to contact is also possible in a more formal style.
With whom did you attend the conference?	Whom	The pronoun follows the preposition with.
Who is responsible for this report?	Who	The pronoun is the subject of is.
The client to whom we sent the proposal	Whom	It is the object of the preposition to.
To what extent did the changes affect the results?	What	To what extent is the standard expression for asking about degree.

Frequently Asked Questions About Who and Whom

Is It “To Who” or “To Whom”?

To whom is the preferred form in traditional formal grammar because whom is the object form used after a preposition. In everyday English, people often say “Who are you talking to?” Both patterns are common, but they suit different levels of formality.

What Is the Difference Between Who and Whom?

Who is a subject pronoun, while whom is an object pronoun. Use who for the person performing an action and whom for the person receiving an action or following a preposition in formal English.

Why Does Whom Follow the Preposition To?

The preposition to normally takes an object. Just as standard formal English uses to him rather than to he, it uses to whom rather than to who.

Is “To Who” Grammatically Correct?

The phrase occurs in informal English, but traditional formal grammar generally favors to whom. In a conversational sentence such as “Who should I give this to?”, using who is widely accepted because the preposition appears at the end.

Is “Who To” or “Whom To” Correct?

Both can occur, depending on the sentence and level of formality. “I don’t know who to ask” is natural modern English, while “I don’t know whom to ask” follows the traditional object-pronoun distinction more strictly.

How Do I Remember When to Use Who or Whom?

Use the he/him test. If you would answer with he, choose who. If you would answer with him, choose whom in the formal construction. For example, “Who called?” — “He called”; “Whom did you call?” — “I called him.”

Is Whom Still Used in Modern English?

Yes. Whom remains part of standard English, especially in formal writing, preposition-first constructions, and established expressions such as “To whom it may concern.” It is less common in casual conversation, where who often takes its place.

Is “To Which” Correct Grammar?

Yes. To which is correct when which refers to a thing, choice, or other suitable non-person referent. For example, “To which address should I send the package?” When asking about degree, use the more natural expression “to what extent.”

Conclusion

The difference between whom or who is easier to understand when you focus on grammatical role rather than word order. Use who when the pronoun is the subject of a clause. Use whom when it is the object of a verb or preposition in traditional formal English.

For example, “Who called you?” is correct because who performs the action. “To whom did you speak?” is the formal choice because whom follows the preposition to. In everyday conversation, however, “Who did you speak to?” is natural and widely accepted.

When in doubt, use the he/him test, check the pronoun’s role in its own clause, and consider your audience. These simple steps will help you choose the right form and write clearer, more natural English.