who’s, whose

Because who’s and whose sound alike, they are easily confused. Writers mistakenly treat the contraction who’s as a possessive form because of the apostrophe s.

Use who’s

• as the contraction of who is
  • Jenna is the cross-country skier who’s (who is) winning the most races this year.
  • Who’s (Who is) your dentist?
• as the contraction of who has
  • Who’s (Who has) been eating my chocolate fudge brownies?

Use whose

• as the possessive form of who
  • Jenna is the cross-country skier whose performance is the most outstanding this year.
  • Whose cat is sitting on my new car?
  • These are my snowshoes. Whose are those?
  • Singer Caroline Savoie, whose hometown is Dieppe, has won many awards, including the SOCAN Best Song Award.
• as a possessive form of which
  • This is a nation whose time has come.
    [= the time of which has come]
  • The bicycle whose chain is broken is mine.
    [= the chain of which is broken)

Note: Use the possessive whose not only for people but also for animals and even things, in order to avoid the awkward construction of which.

Tip

If you can substitute who is (or who has) in your sentence, then who’s is correct. In all other cases, use whose.