Is it to who or to whom?

To whom (not “to who”) is the correct choice in the formal letter greeting “To Whom It May Concern.”

“To whom” is also the correct option at the beginning of a question (e.g., “To whom shall I give it?”).

But bear in mind that “whom” has a very formal stylistic effect, which you may want to avoid. In most everyday contexts, it is better to use “who” and put the preposition “to” at the end (e.g., “Who shall I give it to?”).

“To whom” (not “to who”) is also grammatically correct at the beginning of an adjective clause (e.g., “The man, to whom she was married for ten years, did not attend”). But again, “who” is often the better option, with “to” in a later position (e.g., “The man, who she was married to for ten years, did not attend”).

Using “to whom” in a restrictive adjective clause produces sentences that can be difficult to read (e.g., “This is the man to whom she was married”). Here you can leave out “whom” altogether and move “to” to a later position (e.g., “This is the man she was married to”).

The QuillBot Grammar Checker can help ensure you’re using “who” and “whom” correctly.