Apostrophe rules

The apostrophe’s two jobs

The apostrophe (‘) looks small, but it causes more mistakes than almost any other mark. Luckily, it has only two jobs:

1. Showing ownership (possession)
2. Showing missing letters (contractions)

If neither job applies, you do not need an apostrophe.

Job 1: Showing ownership

A possessive word shows that something belongs to someone.

Singular possessive

For one owner, add ‘s. This is the singular possessive.

the cat’s toy, Ana’s book, my teacher’s desk, the sun’s rays

This works even if the name ends in s: James’s bike, the bus’s wheels. (Some style guides allow James’; both are acceptable if you are consistent.)

Plural possessive

For more than one owner, this is the plural possessive. First make the plural, then decide:

• Plural ends in s: add only ‘: the cats’ toys, the teachers’ lounge, the Smiths’ house
• Plural does not end in s: add ‘s: the children’s books, the men’s team, the mice’s cheese

Step-by-step check:

1. Who is the owner? the girls
2. Write the owner word exactly: girls
3. Ends in s? Add ‘ → girls’. Doesn’t? Add ‘s.

Joint and separate ownership

• Joint possession (shared): add ‘s to the last name only: Mia and Leo’s dog (one dog they share).
• Separate ownership: add ‘s to each name: Mia’s and Leo’s dogs (each has their own).

Ownership with time and money

Apostrophes also show "of" with time and amounts: one day’s work, two weeks’ notice, a dollar’s worth.

Job 2: Contractions

A contraction joins two words and drops letters. The apostrophe marks the gap.

do not → don’t, I am → I’m, they are → they’re, it is → it’s, we will → we’ll

Put the apostrophe where the letters were removed: didn’t (not did’nt).

Apostrophes also replace numbers in years: the ’90s (the 1990s).

When NOT to use an apostrophe

Plurals

Ordinary plurals never need an apostrophe.

I bought three apples. not apple’s
The 1990s not 1990’s
Many DVDs not DVD’s

(One exception: lowercase letters, to avoid confusion: mind your p’s and q’s.)

Possessive pronouns

Pronouns that show ownership never use apostrophes: his, hers, its, ours, yours, theirs, whose.

The dog wagged its tail. (it’s would mean it is)
Is this book yours? (not your’s)

The it’s/its test

This is the single most common apostrophe mistake. Try replacing the word with it is or it has.

• It’s raining. → It is raining. ✓ So use it’s.
• The tree lost it’s leaves. → The tree lost it is leaves? ✗ So use its.

Worked examples

Example 1: The bikes belong to the boys. → the boys’ bikes.

Example 2: The toys belong to the baby. → the baby’s toys.

Example 3: The room belongs to the women. → the women’s room.

Example 4: Fix: Their going to they’re grandparent’s house. → They’re going to their grandparents’ house.

Common mistakes

• Banana’s $1 ✗ → Bananas $1 ✓
• The dog chased it’s tail ✗ → its tail ✓
• The childrens’ books ✗ → the children’s books ✓
• Your’s truly ✗ → Yours truly ✓

Try it yourself

1. Write the possessive: the hat of the clown, the hats of the clowns.
2. Write the possessive: the books of the people.
3. Contraction: should not, they will.
4. Fix it: The cat’s are sleeping in it’s bed.

Answers: 1. the clown’s hat; the clowns’ hats. 2. the people’s books. 3. shouldn’t, they’ll. 4. The cats are sleeping in its bed.

Tip for families

Hunt for apostrophe mistakes on signs, menus and flyers. Kids love catching grown-ups making errors! Take a photo, explain the correct version, and keep a "wall of fame" of the best finds.

Quick recap

• Apostrophes show ownership or missing letters.
• Singular: add ‘s. Plural ending in s: add ‘. Other plurals: add ‘s.
• Never use apostrophes for plurals or possessive pronouns.
• Test it’s/its by saying "it is".