's and of (Possession)

People and Animals: Use ’s

When the owner is a person or an animal, use ’s (apostrophe + s).

• The manager’s schedule is full today.
• Have you met Sarah’s new assistant?
• Be careful with the dog’s leash.

You can drop the noun after ’s when the meaning is clear:

• This laptop isn’t mine. It’s my colleague’s. (= my colleague’s laptop)

When the owner is described by a long phrase, switch to of:

• the office of the woman who interviewed us (not the woman who interviewed us’s office)

Note that ’s can also describe what something is for:

• a women’s restroom (= a restroom for women)
• a children’s menu (= a menu for children)

Singular vs. Plural Owners

The position of the apostrophe changes depending on number.

With joint possession, put ’s on the last name only:

• Have you been to Tom and Lisa’s new office?

Things and Ideas: Use of

For objects, abstract ideas, and concepts, use of instead of ’s.

• the results of the audit (not the audit’s results)
• the title of the report
• the owner of the building

This is especially true for position and location words:

Organisations and Places: Both Work

When you talk about a company, government, city, or country, you can use either form.

• the company’s new policy or *the new policy of the company*
• the city’s population or *the population of the city*
• *Japan’s economyorthe economy of Japan*

Time Words: Use ’s

With time expressions like yesterday, today, tomorrow, next week, Monday, etc., use ’s.

• Did you read yesterday’s sales report?
• *Next week’s deadline has been pushed back.*
• *Tomorrow’s agenda looks busy.*

With periods of time, use ’s for singular and s’ for plural:

• I need a week’s notice before you take leave.
• She has three weeks’ vacation saved up.
• The office is just five minutes’ walk from the station.

Quick Self-Check