Whose vs. Who’s: Possession or Contraction

These two forms sound identical, but their jobs are different. The apostrophe in who’s marks omitted letters. It does not mark possession. Possession belongs to whose.

Use whose for possession

Use whose to ask about ownership or association: “Whose notebook is on the desk?” It can also introduce a clause: “The candidate whose essay won the award revised it twice.” In both examples, whose links a person to something connected with that person.

Use who’s for who is or who has

Who’s is short for who is (“Who’s ready?”) or who has (“Who’s finished the assignment?”). The intended expansion depends on the sentence. If who is or who has fits grammatically and keeps the meaning, the contraction is appropriate.

A quick substitution test

1. Read the sentence with who is in place of who’s.
2. If that fails, try who has.
3. If neither expansion works, use whose if the sentence expresses possession or association.

Common trap

“Who’s book did you borrow?” is incorrect because “who is book” and “who has book” do not work as the intended question. Write “Whose book did you borrow?” Conversely, “Whose going to present?” should be “Who’s going to present?” because the sentence means “Who is going to present?”

Use a substitution test that preserves the grammar

To decide whether who’s is correct, replace it with “who is” first. If the expanded sentence is grammatical and keeps the intended meaning, the contraction works: “Who’s leading the discussion?” becomes “Who is leading the discussion?” If that does not fit, try “who has”: “Who’s completed the review?” means “Who has completed the review?” If neither expansion makes sense, the sentence likely needs whose for a relationship or possession.

The test must work in the whole sentence, not just beside the word. “The author who’s book won the prize” fails because neither “who is book” nor “who has book” expresses the intended relationship. “The author whose book won the prize” shows which book is associated with the author. In a question such as “Whose arriving first?”, the intended meaning is “Who is arriving first?”, so who’s is required.

Whose can refer to people and things

Whose is commonly used for a person's possession, but it can also identify an associated person, organization, or thing: “a company whose policy changed” or “a report whose findings were questioned.” It introduces a modifying clause and does not require an apostrophe. In formal writing, do not replace it with “who’s” merely because the words sound alike.

Do not confuse possessive forms

• Who’s = who is or who has; the apostrophe replaces omitted letters.
• Whose = possessive form of who; it identifies the person or thing associated with a noun.
• Whom’s is not a standard substitute for whose. In a construction asking ownership, recast the sentence with whose.
• The apostrophe rule for nouns such as “the teacher’s desk” does not apply to possessive pronouns such as whose, hers, or theirs.

Edit for meaning, not sound

Read the sentence aloud with the intended expansion. If the sentence asks for identity or action—“Who is speaking?”—choose who’s. If it asks which person's or organization's item, decision, or characteristic is involved, choose whose. Then reread the complete sentence to confirm that the following noun or verb fits. This is more reliable than trying to hear a difference in speech, where the two forms are pronounced alike.

Use whose to ask about or show possession

Whose is the possessive form of who and is also used as a possessive relative determiner: “Whose notes are these?” and “The candidate whose notes were missing called the office.” It identifies the person who owns or is associated with something. Like his, her, or their, whose does not take an apostrophe.

Who’s is a contraction of who is or who has: “Who’s ready?” means “Who is ready?” “Who’s completed the form?” means “Who has completed the form?” Expand the contraction in place; if neither who is nor who has makes sense, use whose.

Apply the expansion test in questions and clauses

In “Who’s responsibility is it?” expanding to “Who is responsibility” does not work, so the correct form is “Whose responsibility is it?” In “Do you know who’s arriving?” the expansion “who is arriving” works. The word after the blank can be a helpful clue—whose often precedes a noun—but the expansion test handles more sentence patterns.

Whose can introduce a dependent clause without asking a direct question: “The researcher whose article we read will speak today.” It still shows a relationship between the researcher and article. Who’s remains a contraction wherever it appears; it does not become possessive because it is followed by a noun.

Do not confuse whose with who or whom

Who is generally used for a subject or subject complement; whom is traditionally used for an object. Whose marks possession. These forms answer different grammatical questions: who performed an action, whom the action affected, and whose item or quality is involved. In “Whose did you borrow?” the intended possession is clear but the sentence may sound incomplete; “Whose book did you borrow?” supplies the noun.

In informal English, who is common where formal grammar traditionally expects whom. A standardized editing question may test the traditional subject-object distinction, but it is separate from the whose/who’s spelling choice. First expand who’s; then check whether the possessive relationship is intended.

• Use whose for possession; no apostrophe is needed.
• Expand who’s to who is or who has.
• Use whose before a noun when asking who owns or is linked to it.
• Whose can introduce a relative clause.
• Do not confuse possession with the subject/object distinction between who and whom.

Exam takeaway

Do not use the apostrophe as a general sign of ownership. Who’s expands to who is or who has; whose shows possession or association. Test the whole sentence, not just the sound of the word.

Use the concept in a question

Whose is the possessive form of who and can refer to a person or, in standard usage, an organization or thing: “Whose folder is this?” It also introduces a relative clause: “The student whose work improved received feedback.” Who’s is a contraction of who is or who has. Expand it in the sentence to test the choice: “Who’s prepared?” means “Who is prepared?” The apostrophe marks omitted letters, while whose indicates possession without one. As with its and it’s, do not add an apostrophe merely because ownership is involved; possessive pronouns have their own forms.