What is the difference between 'who' and 'whom'?

A quick trick: try answering the question using "he" or "him." If "he" fits, use "who." If "him" fits, use "whom" — both "whom" and "him" end in "m," which makes it easy to remember.

Examples

• "Who called you?" → "He called you." → use "who"
• "Whom did you call?" → "I called him." → use "whom"

Why "whom" feels rare

In casual spoken English, "whom" has largely fallen out of everyday use, with many speakers using "who" in both roles ("Who did you call?"). "Whom" is still expected in formal writing, especially directly after a preposition, like "to whom it may concern" or "with whom are you traveling."