The apostrophe is an important piece of punctuation. The main uses of apostrophes are to show ownership (e.g. ‘Charlie is Jenny’s cat’ means the cat named Charlie belongs to Jenny) and to show missing letters in words (e.g. it’s = it is or it has; should’ve = should have). In academic writing, words that use apostrophes for missing letters (i.e. contractions and abbreviations) are considered informal language and should be avoided. It is important to know the rules for apostrophes as a misplaced apostrophe can change the meaning of a sentence (e.g. the teacher who lost the students’ books—more than one student—is a lot more worried than the teacher who lost the student’s books—one student). This page covers:

Grammar checkers will not help you much with your apostrophes. They can alert you about apostrophes for most contractions (e.g. don’t) and about some possessive apostrophes (e.g. Jack’s horse), but the alert may be incorrect or miss the error altogether. You will need to proofread your work yourself and apply the rules for using apostrophes correctly in your writing.

Singular and plural words indicating ownership

For singular nouns, indefinite pronouns (e.g. anybody, someone, nobody) and words already ending in s, place the apostrophe before the s when indicating ownership.

CORRECT:The student’s essays were impressive.

CORRECT: Someone’s books were left outside the library.

CORRECT: James’s assignment received a high distinction. 

INCORRECT: The customers complaints were ignored.


CORRECT: The customer’s complaints were ignored.



For plural nouns ending in s, place the apostrophe after the s when indicating ownership.

CORRECT: The students’ essays were impressive.

CORRECT: The customers’ complaints were ignored.

INCORRECT: A union member’s barbecue will be held on Sunday. 


CORRECT: A union members’ barbecue will be held on Sunday. 


For plural nouns not ending in s (e.g. people, women, men, children, data, criteria, media, radii), place the apostrophe before the s when indicating ownership.

CORRECT: The people’s decision will be final.

CORRECT: The women’s movement campaigned for equal pay.

INCORRECT: Mens’ health was an issue in the Federal election.


CORRECT: Men‘s health was an issue in the Federal election.


For joint possession and for compound nouns, apply the rules only to the last noun.

CORRECT: Peterson and Smith‘s journal article was well-received.

CORRECT: Peterson‘s and Smith‘s journal articles were well-received.

CORRECT: My father-in-law’s books won a prize.

CORRECT: The Leaders of the Oppositions’ memoirs were published.

INCORRECT: The mother‘s-in-laws annual meeting was cancelled.

Revision, assuming it is a meeting of numerous mothers-in-law

CORRECT: The mothers-in-law‘s annual meeting was cancelled.

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Time or quantity

Apostrophes can be used to indicate time and quantity expressions.

  • It’s an hour’s walk from here.
  • Breaking a mirror is seven years’ bad luck.
  • I’ll have three dollars’ worth.

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The plurals of words

COMMON MISTAKE – Do not use apostrophes to form plurals unless there is ownership of someone or something.

INCORRECT: Please replace the trolley‘s.

CORRECT: Please replace the trolleys.

INCORRECT: DVD‘s were issued to students.


CORRECT: DVDs were issued to students.

CORRECT: The DVD‘s broken.

CORRECT: The DVD‘s cover is missing.

INCORRECT: After the 1980‘s, interest rates varied greatly.

CORRECT: After the 1980s, interest rates varied greatly.


Use an apostrophe to avoid confusion when forming the plural of some words and letters, but not numbers.

CORRECT: Remember to dot your i’s and cross your t’s.

CORRECT: There are too many but’s and and’s in this sentence.

INCORRECT: I am at 6‘s and 7‘s about whether to go to the concert.

CORRECT: I am at  6s and 7s about whether to go to the concert. 

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The shortened forms of words

Use apostrophes to show missing letters in words. (Note: it is best to generally avoid the use of shortened forms of words in academic writing as they are regarded as informal language.)

  • it’s
  • the ’60s generation
  • Jack yelled, “Are ya’ comin’ to m’ place for a barbie?”

Do not use an apostrophe (or full stop) at the end of common abbreviations.

  • Doctor can be abbreviated to Dr (no punctuation) as in Dr Smith.
  • Department can be abbreviated to Dept (no punctuation) as in Dept of Education.

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Rules to avoid incorrect use of apostrophes

  • Do not put an apostrophe on any word that ends in s unless it is for missing letters or to show ownership.
  • Do not use an apostrophe for possessive pronouns (e.g. its, whose, his, hers, ours, yours, theirs, yours) even though someone owns something. (e.g. That book is yours.)
  • Do not use an apostrophe for institutional names, place names, street names, maps and public signs (e.g. The Teachers Federation, Kings Cross, Smiths Road, Petersons Peak, Jacksons Park).
  • Do not use an apostrophe if the word before the noun is more descriptive than possessive. (e.g. I have my drivers licence, but that driver’s licence is lost. I have my travellers cheque, but that traveller’s cheque was stolen.)
  • Do not use it’s in your writing unless you mean ‘it is’ or ‘it has’.

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