The English Department's
Quick Guide to Using Apostrophes

Use an apostrophe to show that a noun possesses something.

If the noun is singular, add an apostrophe and an s.

For plural nouns ending in s, add only an apostrophe.

For plural nouns that do not end in s, add an apostrophe and an s.

Use an apostrophe to show that something has been left out of contractions. Warning: Do not use an apostrophe to form plurals!

There are exceptions to this rule, but these are so rare I’m not going to bother with them here (consult a good grammar book if you’re curious).

Warning: Personal pronouns do not take an apostrophe. Don't put one in at all in these cases! Warning: Do not confuse it’s with its or who’s with whose.

It’s is a contraction of it is or it has.

Its is the possessive form of it.

Who’s is a contraction of who is or who has.

Whose is the possessive form of who.


© The English Department 1999