Grammar Monster
Grammar Monster

Apostrophes before S (with Examples)

Apostrophe before S

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

As you probably already know, apostrophes are used for possession. For example:
  • The cat's dinner.
  • The cats' dinner.
The big question with an apostrophe used for possession is whether to put your apostrophe before the letter s or after the letter s.

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

What's the Possessor?

In the examples above, the cat (or cats) is known as the possessor. The possessor is the thing that owns whatever follows. (Be aware that the word owns is used in a very loose sense. The possessive apostrophe is not always about possession or ownership.) Now we know the word possessor, we can say the rule properly:
If the possessor is singular, the apostrophe goes before the s.
If the possessor is plural, the apostrophe goes after the s.
Note: Your decision on where to put the apostrophe only depends on the number of possessors. The number of things being possessed is irrelevant. For example:
  • The cat's dinner.
  • (one cat, one dinner)
  • The cat's dinners.
  • (one cat, lot of dinners)
  • The cats' dinner.
  • (lots of cats, one dinner)
  • The cats' dinners.
  • (lots of cats, lots of dinners)
The only things that matters is how many cats there are. The number of dinners is irrelevant.

Exceptions to the Rule with Possessive Apostrophes

Unfortunately, there are some exceptions to the rule above.

Plural Words Not Ending in S

With plural words that do not end in s (e.g., people, men, children), you put the apostrophe before the s (as though they were singular words). For example:
  • He is the people's poet.
  • All television is children's television. (Richard P. Adler)
Singular Words Not Ending in S

With singular words that end in s (e.g., Wales, Paris, Moses), you can add ' (i.e., just an apostrophe) or 's. For example:
  • It is Charles' birthday.
  • It is Charles's birthday.
  • (Both versions are correct.)
Read more about apostrophe for possession.
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:
  • doges dinner
  • dogses dinner
  • childrenes dinner
  • Charleses 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.

This process still works for everything. 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.