Apostrophes
An apostrophe shows ownership or a missing letter; it never makes a word plural.
Updated October 29, 2026
The rule
One owner: add 's (the dog's bowl). More than one owner ending in s: add only the apostrophe (the dogs' bowls). A plural that doesn't end in s takes 's (the children's books).
Plain plurals take no apostrophe: three apples, the 1990s, the Smiths.
Examples
The apple's are on sale.The apples are on sale.Both teams's coaches shook hands.Both teams' coaches shook hands.
Quick test: Say "belonging to": "the coaches belonging to both teams" tells you the owner is plural.
Try it: find the mistake
The mistake in each sentence is highlighted. Say the fix out loud, then open the answer.
The cookie's are still warm.
The cookies are still warm.
This is a plain plural, not ownership, so it takes no apostrophe.
That is my sisters backpack.
That is my sister's backpack.
The backpack belongs to one sister: sister's.
The childrens toys were everywhere.
The children's toys were everywhere.
Children is already plural and doesn't end in s, so add 's.
All three teacher's cars were parked in a row.
All three teachers' cars were parked in a row.
The cars belong to three teachers, a plural ending in s, so the apostrophe goes after the s.
Where this rule is tested
Questions people ask
What is the rule for apostrophes?
An apostrophe shows ownership or a missing letter; it never makes a word plural. One owner: add 's (the dog's bowl). More than one owner ending in s: add only the apostrophe (the dogs' bowls). A plural that doesn't end in s takes 's (the children's books).
How can I check my apostrophes quickly?
Say "belonging to": "the coaches belonging to both teams" tells you the owner is plural.
Where can I practice this for free?
In Owl Test Prep's Daily Grammar Fix: one sentence a day for everyone, plus practice sets of five on this rule. It is free, with no account.