Mastering Possessives: The Correct Use of Apostrophes in English

We use -’s (apostrophe + s) mostly for people or animals:

Tom’s computer isn’t working. (not the computer of Tom)

How old are Chris’s children? (not the children of Chris)

What’s (= What is) your sister’s name?

What’s Tom’s sister’s name?

Be careful. Don’t step on the cat’s tail.

You can use -’s without a noun after it:

This isn’t my book. It’s my sister’s. (= my sister’s book)

We do not use -’s after a long group of words. So we say:

my friend’s mother
but the mother of the man we met yesterday (not the man we met yesterday’s mother)

Note that we say a woman’s hat (= a hat for a woman), a boy’s name (= a name for a boy),
a bird’s egg (= an egg laid by a bird) etc.

With a singular noun we use -’s:

my sister’s room (= her room – one sister)
Mr Carter’s house (= his house)

With a plural noun (sisters, friends etc.) we put an apostrophe (’) after s:

my sisters’ room (= their room – two or more sisters)
the Carters’ house (= their house – Mr and Mrs Carter)

If a plural noun does not end in -s (for example men/women/children/people) we use -’s:

the men’s changing room                             a children’s book (= a book for children)

You can use -’s after more than one noun:

Jack and Karen’s children                              Mr and Mrs Carter’s house

For things, ideas etc., we normally use of:

the temperature of the water   (not the water’s temperature)
the name of the book                the owner of the restaurant

We say the beginning/end/middle of … / the top/bottom of … / the front/back/side of … :

the beginning of the month (not the month’s beginning)
the top of the hill                  the back of the car

You can usually use -’s or of for an organization (e.g., a group of people). Here are some examples:

The government’s decision or the decision of the government

The company’s success or the success of the company

We also use -’s for places. Here are a few examples:

The city’s streets       The world’s population             Italy’s prime minister

We use -’s with time words such as yesterday, next week, etc.:

Do you still have yesterday’s newspaper?

Next week’s meeting has been cancelled.

In the same way, you can say:  Today’s / Tomorrow’s / This evening’s / Monday’s, etc.

We also use -’s (or -s’ with plural words) with periods of time:

I’ve got a week’s holiday starting on Monday.

Julia has got three weeks’ holiday.

I live near the station – it’s only ten minutes’ walk.

Try this exercise to test your grammar.

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