Add 's to form the possessive of most singular nouns.
- My father's brother is my uncle.
- The tree's leaves are green.
- An oyster's shell is very hard.
Add 's to form the possessive of irregular pleural nouns not ending in s.
- The men's restroom is open.
- People's opinions often differ.
- All the mice's tails are white.
Add 's to form the possessive of indefinite pronouns not ending in s.
- It's anybody's guess.
- Someone's dog is barking.
- It's nobody's fault but mine.
Add 's to form the possessive of singular proper nouns ending in an s, x or z.
- We ate lunch at Chris's place.
- Max's surgery was a success.
- I put Liz's necklace in the drawer.
Note: A less common practice is to add only an apostrophe to form the possessive of singular nouns ending in an s or "eez" sound if adding 's would create an awkward pronunciation.
Add only an apostrophe to form the possessive of pleural nouns ending in s.
- The workers' jobs are hard.
- Seatbelts are for drivers' safety.
- I was invited to the Smiths' party.
To form the possessive of compound nouns, add 's to the last word only.
- The commander-in-chief's decision is final.
- My washing machine's agitator is broken.
- The vice-president's job is easy.
To show joint possession, make only the last noun possessive.
- Mike and Cindy's car was stolen.
- Jack and Jill's pail is full of water.
- Bob and Ted and Carol's bill is paid.
To show individual ownership, make all nouns possessive.
- Mike's and Cindy's cars were stolen.
- Jack's and Jill's pails are full of water.
- Bob's and Ted's and Carol's bills are paid.
Do not use an apostrophe with possessive pronouns.
- Yours is the house on the right. (not your's)
- The crow held a worm in its beak. (not it's)
Some style guides recommend the use of an apostrophe to form certain pleurals, while others do not.
- Her report card showed three A's and two B's. (Modern Language Association)
- Her report card showed three As and two Bs. (Chicago Manual of Style, Turabian)
Use an apostrophe to form contractions. Numbers as well as words can be contracted. The apostrophe indicates omitted letters or numbers.
- I'm getting tired of you. (I'm = I am)
- The '89 hurricane devastated Charleston. ('89 = 1989)
- Fish 'n' chips are tasty. (fish 'n' chips = fish and chips)
Note: Do not confuse word contractions with possessive pronouns.
- Your is a possessive pronoun.
- You're is a word contraction for you are.
- Their is a possessive pronoun.
- They're is a word contraction for they are.
- Its is a possessive pronoun.
- It's is a word contraction for it is.