's (Kate's camera/my brother's car)

The possessive 's shows that one noun owns or is connected to another noun. We use it with people, animals, organisations, time expressions and some measurements. It is a short way to show possession instead of using the of-construction.

• Add 's to a singular noun: my brother's car.
• For plural nouns already ending in s, add only an apostrophe: the employees' desk.
• For irregular plurals not ending in s, add 's: the children's toys.
• Use 's with names and compound nouns: Kate's camera, my sister-in-law's office.

Remember whether the noun is singular or plural and whether it already ends in s:

• Singular nouns → add 's (the manager's email).
• Plural nouns ending in s → add only an apostrophe after s (the managers' email).
• Plural nouns not ending in s → add 's (the children's books).
• For names ending in s, you can add 's or just ' depending on style, but in speech you'll still pronounce /ɪz/ (e.g., James's report or James' report).

When in doubt, choose clarity: use 's for singular and ' for regular plurals.

Watch for these universal errors when using the possessive 's:

• Confusing possessives with contractions: it's (it is) vs its (possessive).
• Placing the apostrophe in the wrong place for plural nouns (e.g., writing employees's).
• Using 's with a noun that should use the of-construction for non-human abstract relationships (style preference).
• Adding both an apostrophe and extra s to plural nouns that already end in s (incorrect: managers's).
• Omitting the apostrophe entirely (companys instead of company's).

Always check whether the noun is singular/plural and whether it ends in s before adding an apostrophe.