Using the apostrophe

Study guide
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This guide has been written to give a simple explanation of the use of the apostrophe (’). It explains the main rules for its use, and gives examples of commonly encountered problems.

Other Useful Guides:  Sentence Structure, Using the comma, Using the semi-colon and colon.

The apostrophe has two main uses

  • It replaces missing letters when we join words e.g. I can't swim

This is known as a contraction.

  • It shows ownership e.g. this is John’s book.


When contractions are used, the apostrophe replaces the letter or letters that were removed to make a shorter word:

do not becomes - don’t .

The apostrophe replaces the missing letter, in this case the o .

Further examples are:

I will becomes - I’ll

you are becomes - you’re

they are becomes - they’re

Whilst it is important to understand the function of contractions, their use is not usually appropriate in academic writing.


Apostrophes are also used to show ownership - they make a word possessive. To make a word possessive follow the three simple rules given below.

1. If the word is singular add  ’s


the student’s books - meaning the books belonging to the student.

Further examples are:

the boss’s armchair; the government’s legislation.

2. If the word is a plural but does not end in  s add  ’s :

women’s rights - meaning the rights of women.

Further examples are:

children’s playground - meaning the playground for children;

men’s changing rooms - meaning the changing rooms for men.

3. If the word is plural and ends in  s just add an apostrophe:

the studentslibrary books - meaning the books belonging to the students.

Further examples are:

the ladies football league; the workersrights.

Common problems in using apostrophes

The apostrophe is frequently misused. Words that cause particular problems are: its / it’s and whose / who’s.

Its / it’s

Use its when you want to show possession:

the government abandoned its policy.

Its belongs to a group of words that are already possessive. Other examples are: it is hers; it is yours. These words are already possessive; they do not need apostrophes to indicate possession.

Use it’s when you want to shorten it is:

it’s a nice day.

It’s is a contraction of it is . The apostrophe replaces the missing i.

Whose / who’s

Use whose when you want to show possession:

the student whose notes I borrowed.

Whose belongs to the same group of possessive words as its. It does not need an apostrophe to denote possession.

Use who’s when you want to shorten who is:

the student who’s coming to visit.

Who’s is a contraction of who is. The apostrophe replaces the missing i.

Remember: just because a word ends in s, it does not mean it needs an apostrophe! An apostrophe is added to show possession or to replace a missing letter or letters in contractions. If you are unsure when to use an apostrophe, check your use of the apostrophe falls under one of the rules outlined in this guide.

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