Apostrophes

Form

An apostrophe does two jobs: it shows possession and it marks letters left out of a contraction (the manager's office, it's for it is).

For possession, add apostrophe plus s to a noun that does not already end in a plural -s (the dog's bowl, the children's room, James's car — some styles write James' car), and add the apostrophe alone to a plural that does (the managers' meeting). In a contraction the apostrophe sits exactly where the missing letters were (I have becomes I've, should have becomes should've). Possessive pronouns never take one, because its, yours, hers, theirs and whose are already possessive.

When to Use It

1. 1

   Showing what belongs to one person or thing

   My doctor's appointment is at three.

2. 2

   Showing what belongs to a plural that already ends in -s

   The managers' meeting ran late.

3. 3

   Showing what belongs to an irregular plural

   The women's team won the championship.

4. 4

   Marking the missing letters in a contraction

   I've seen that movie three times.

5. 5

   Joint ownership, where only the last name takes the apostrophe

   Maria and Tom's apartment is on the fifth floor.

6. 6

   Telling it's from its by expanding the contraction

   It's raining, so the dog wants its blanket.

Common Mistakes

• Its for it's: write It's raining, not Its raining — it's is only ever it is or it has.
• An apostrophe on a plain plural: write two managers, not two manager's — a plural that owns nothing takes no apostrophe.
• An apostrophe on a possessive pronoun: write The book is hers, not The book is her's — hers, yours, theirs and its are possessive already.
• Whose and who's: write Whose turn is it?, not Who's turn is it? — who's can only mean who is or who has.
• An apostrophe in a decade: write the 1990s, not the 1990's — the -s here is a plural, not a possessive.