Who vs Whom: A Simple Test for Business Writing

"To whom it may concern." "Who should I send this to?" "Whom should I send this to?" Whom shows up in formal letters and almost never in conversation, so many writers are unsure when it is actually required. The rule itself is not complicated. The harder part is knowing when following it strictly makes your writing better and when it makes it sound stiff.

1. The rule in one line

Merriam-Webster explains that who refers to someone performing the action of a verb, and whom refers to someone receiving the action. In grammar terms, who is a subject and whom is an object. Its dictionary entry defines whom simply as the objective case of who, used as the object of a verb or of a preposition.

• Who = the one doing the action, like he, she, or they.
• Whom = the one receiving the action, like him, her, or them.

2. The he/him test

Since who works like he and whom works like him, you can test a sentence by turning it into a statement and plugging in he or him.

Questions:

• "___ approved the budget?" becomes "He approved the budget." He works, so use who: "Who approved the budget?"
• "___ should I send the invoice to?" becomes "I should send the invoice to him." Him works, so the formal choice is whom: "Whom should I send the invoice to?" or "To whom should I send the invoice?"

Merriam-Webster uses this same method, turning a question into a statement with an unknown "X" and checking whether X is the subject or the object.

Relative clauses (the part of a sentence that describes a person):

• "The manager ___ hired me is leaving." Split it: "She hired me." Subject, so who.
• "The candidate ___ we interviewed has accepted." Split it: "We interviewed her." Object, so whom in formal writing.

3. After a preposition, whom is standard

Merriam-Webster says that when the word directly follows a preposition, whom is the preferred choice, as in "For whom was the gift intended?" Cambridge Dictionary agrees that the most common use of whom is with a preposition.

That is why fixed formal phrases use it:

• "To whom it may concern"
• "the colleague with whom I share an office"
• "the clients for whom we built the dashboard"

Cambridge adds one important detail. When you use who with a preposition, the preposition moves to the end of the clause, not right before who. Its example contrasts "the one who I know I can rely on" with the incorrect "the one on who I know I can rely." So you can write either:

• "the person to whom you sent the file" (formal)
• "the person who you sent the file to" (natural, informal)

But not "the person to who you sent the file."

4. When who is perfectly fine

Merriam-Webster is clear that whom often sounds fussy and unnatural in ordinary speech and writing, even when it is technically correct. It gives "It depends on whom you ask" as an example and says that in cases like this it is perfectly standard to use who instead. Its summary advice is that when in doubt, you can generally just use who.

Cambridge describes whom as used in formal styles or in writing, much more common in writing than in speaking. Its table of relative pronouns notes that in many defining clauses you can also leave the pronoun out entirely: "The parents (whom/who/that) we interviewed were all involved in education."

5. Choosing for business writing

6. Before and after

Before: Whom is responsible for the client account? After: Who is responsible for the client account? Why: "He is responsible," so it is a subject.

Before: The vendor who we contacted last week has replied. Formal option: The vendor whom we contacted last week has replied. Simplest option: The vendor we contacted last week has replied. Why: "We contacted them," so it is an object. All three are acceptable; the last avoids the choice.

Before: Please tell me to who I should send the signed form. After: Please tell me to whom I should send the signed form. Or: Please tell me who I should send the signed form to.

7. Key takeaways

• Who is the subject (like he), and whom is the object (like him).
• Turn the sentence into a statement and test with he or him to find the right form.
• Directly after a preposition, use whom, as in "to whom" and "with whom."
• In everyday writing, who in object position is standard and often sounds more natural.
• Never use whom as the subject of a verb, and when unsure, rewrite or leave the pronoun out.