"Whose" and "who's" sound identical but have completely different meanings. This is one of the most common errors in written English.
The Difference
Whose = possessive form of "who" (shows ownership). Who's = contraction of "who is" or "who has."
Whose (Possession)
Whose asks about or refers to ownership. It can be an interrogative pronoun (question) or a relative pronoun.
In questions:
- Whose phone is ringing?
- Whose is this coat?
- I don't know whose car that is.
In relative clauses:
- The girl whose father is a doctor studies hard.
- The company whose CEO resigned is struggling.
Who's (Contraction)
Who's = who is or who has.
- Who's at the door? (= Who is)
- Who's finished their homework? (= Who has)
- The man who's wearing a black suit is my boss. (= who is)
- She's the one who's been helping me. (= who has)
The Apostrophe Trap
The apostrophe in "who's" indicates a contraction, NOT possession. This confuses many writers because " 's " usually shows possession for nouns.
| Correct | Meaning | | ---------------------- | ---------------- | | Who's coming? | Who is coming? | | Whose bag is this? | The bag of whom? |
Quick Test
Replace with "who is" or "who has." If it makes sense, use who's. If not, use whose.
| Sentence | Test | Answer | | ---------------------------- | --------------------- | --------- | | ___ ready to begin? | Who is ready? ✅ | Who's | | ___ idea was this? | Who is idea? ❌ | Whose | | I know ___ responsible. | who is responsible ✅ | who's | | The boy ___ dog ran away. | who is dog ❌ | whose |
Common Mistakes
| Incorrect | Correct | | ---------------------------------- | ---------------------------------- | | Who's coat is this? | Whose coat is this? | | Whose going to the party? | Who's going to the party? | | The student who's essay won. | The student whose essay won. | | Do you know who's car that is? | Do you know whose car that is? |
Memory Tip
If you can replace the word with "who is" or "who has," use who's. Otherwise, use whose for possession.