Grammar Monster
Grammar Monster

Apostrophes after S (with Examples)

Apostrophe after S

This page is about when to use an apostrophe after the letter s.

If you're a native English speaker, you probably already use apostrophes to show possession. For example:
  • The hamster's cage.
  • The hamsters' cage.
The question everyone asks with an apostrophe used for possession is where to put the apostrophe. Does it go before the letter s or after the letter s?

Here's the rule (using the example above):
If there is one hamster, the apostrophe goes before the s.
If there is more than one hamster, the apostrophe goes after the s.

What Is the Possessor?

In the examples above, the hamster (or hamster) is called the possessor. The possessor is the "owner" of whatever follows. (Be aware that the word owner is used very loosely. Possessive apostrophes do not always denote possession or ownership.) Here is the rule again using the proper terms:
When the possessor is singular, the apostrophe goes before the s.
When the possessor is plural, the apostrophe goes after the s.
Note: The number of things being possessed is irrelevant. For example:
  • The hamster's cage.
  • (one hamster, one cage)
  • The hamster's cages.
  • (one hamster, lot of cages)
  • The hamsters' cage.
  • (lots of hamsters, one cage)
  • The hamsters' cages.
  • (lots of hamsters, lots of cages)
Only the number of hamsters matters. The number of cages is irrelevant.

Interactive Test


The History of the Possessive Apostrophe

The principal function of an apostrophe is to replace a missing letter (e.g., don't, isn't). This is related to the possessive apostrophe.

In old English, possession was shown by adding es to the possessor regardless of whether the possessor was singular or plural. For example:
  • cates dinner
  • catses dinner
  • menes dinner
  • Moseses dinner
Over time, the e was replaced by an apostrophe and if that left an ending of -s's, then the second s was removed.

If you use this process today, you will be right every time. There are no exceptions.
(1) Add es to the possessor
(2) Replace the e with '
(3) If left with s's, change to s'
Read more about using apostrophes.