learn the rule

apostrophes

Apostrophes have two main uses: contractions (joining two words or replacing letters) and possession (ownership).

Contractions

• I will → I'll
• you are → you're
• does not → doesn't (the apostrophe replaces the "o")
• who is → who's (not to be confused with whose)

A quick test: who's that? = who is that? Whose bike is that? = to whom does the bike belong?

Possession

How you punctuate depends on whether the owner is singular or plural.

• Singular owner: word + apostrophe + s. Example: the bike that belongs to John → John's bike.
• Plural owner: word + s + apostrophe. Example: the wheels belonging to lots of bikes → the bikes' wheels.
• Combine the two: John's bikes' wheels (the wheels belonging to the bikes, belonging to John).

Apostrophes are never used to make a plural

• Many things → lots (not lot's).
• Many cars → cars (not car's).
• Same goes for apples, photos, DVDs, CDs, beers.