Whom and which after a preposition

Short answer: After a preposition such as to, with, for or in, use whom for people and which for things: The friend with whom I traveled is Lan. The room in which we study is warm. Never use who or that after a preposition. This form is formal. In everyday English the preposition goes to the end: The boy I gave the book to is Ben.

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At a glance

In short

• After a preposition: whom (people), which (things).
• Never that or who after a preposition.
• Everyday talk: the preposition at the end.

What is the rule for “whom, to whom, in which”?

The rule

preposition + whom (people) or preposition + which (things).

How it looks

to whom · with whom · for whom · in which · with which

What it means

It adds information and keeps the preposition in front. It is formal.

When to use it

Use it in careful writing. In everyday talk we say: the boy I gave the book to.

How it works

• Find the preposition in the describing clause: to, with, for, in, on.
• Put it in front of whom (people) or which (things).
• Do not use who or that right after a preposition.
• In everyday talk, keep the preposition at the end and leave out whom: the boy I gave the book to.

Examples of “whom, to whom, in which”

• The friend with whom I traveled is Lan.
  with whom: a person.
• The room in which we study is warm.
  in which: a thing.
• The teacher to whom I spoke was kind.
  to whom: a person.
• The boy I gave the book to is Ben.
  Everyday: to at the end.
• The woman with whom I work is very patient.
  with whom: a person.
• The pen with which I wrote this is red.
  with which: a thing.
• The people to whom I spoke were kind.
  to whom: people.
• The city in which I was born is small.
  in which: a place.

Common mistakes with “whom, to whom, in which”

• The boy to who I gave the book… → The boy to whom I gave the book…
  After a preposition use whom.
• The house in that I live… → The house in which I live…
  After a preposition never use that.
• This is the girl to I wrote. → This is the girl I wrote to.
  to goes at the end, or before whom.
• The people to which I spoke were kind. → The people to whom I spoke were kind.
  People take whom after a preposition.
• The pen with whom I wrote is red. → The pen with which I wrote is red.
  A pen is a thing: which.

Exceptions: watch out

• leave whom out
  In everyday talk we can leave whom out: the boy I gave the book to.

Formal and everyday forms

The formal form puts the preposition before whom or which. The everyday form puts it at the end.

See also: Describing people with who

Check yourself

1. Fill the gap: “The friend with ___ I traveled is Lan.” (who / whom)
   Show the answer

   whom After a preposition, use whom.

2. Fill the gap: “The room in ___ we study is warm.” (that / which)
   Show the answer

   which After a preposition, use which.

3. Say it in everyday English: “The boy to whom I gave the book”
   Show the answer

   The boy I gave the book to The preposition goes to the end.

How to practice “whom, to whom, in which”

The interactive version adds step-by-step help, spoken instructions and a quick check. One rule card, one sound lesson and the first lesson of every stone are free to try; the rest is part of Full Access. See Full Access.

• Practice lesson: whom, to whom, in which

Questions

Is “whom” still used?

In formal writing and speeches, yes. In everyday talk, most people say who or leave it out.

Can I end a sentence with a preposition?

Yes, in everyday English: Who did you talk to? In formal writing, move the preposition forward.

What is the difference between “who” and “whom”?

Who is the subject (Who called?). Whom is the object, especially after a preposition (To whom did you speak?).

More Texts and Talk rules

• Have you ever …? Experience: have / has + the past form tells about something you did (or never did) in your life, up to now.
• already, yet, just: already, yet and just go with have / has and tell about things that happened a short time ago.
• Present perfect or past simple?: A finished time (yesterday, last week) needs the past simple. Experience up to now needs have + the past form.
• Advice and rules: should, must, have to: should gives advice. must and have to give rules. After them, use the plain action word.
• unless: unless means if not. It says what could stop something.
• as … as, and comparing actions: as … as says two things are the same. not as … as says one is less. For actions use faster or more carefully.

Used in these writing topics

• whom, to whom, in which

Part of the 📘 Grammar tool. Level G6: Texts and Talk. Đọc bằng tiếng Việt.

Written for English learners by the English for Fun team. How we write our lessons · Last updated 2026-11-05.

Reviewed by Chinh Q. Hoang, PhD, founder, English for Fun · 2026-10-30

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