Apostrophes show possession and contractions. Don’t use them for descriptive phrases or to make nouns plural.
Apostrophes show possession
To correctly show possession by using an apostrophe, first ask, ‘Who or what is doing the owning?’
The apostrophe goes straight after the answer.
Example
This is Ariah’s desk.
This is the Murphys’ submission to the inquiry. [More than one person called Murphy were part of a joint submission.]
There are possession rules for using an apostrophe, according to the type of noun.
| Noun type | Rule | Examples |
|---|---|---|
| Singular noun | Add an apostrophe and s | the committee’s report, ASIO’s files |
| Plural nouns that end in letter ‘s’ | Add an apostrophe only | both committees’ reports, the Joneses’ submission |
| Plural nouns that don’t end in letter ‘s’ | Add an apostrophe and s | children’s education, the sheep’s wool |
| Proper names ending in letter ‘s’ | Add an apostrophe and another s, even if you don’t pronounce the final s in the noun | Burns’s report, James’s profession, Ross’s job, Louis’s supervisor |
| More than one noun: individual possession | Add an apostrophe and s after each noun | Smith’s and Miller’s offices |
| More than one noun: joint possession | Add an apostrophe and s after the last noun only | Smith and Miller’s report |
| Singular compound noun | Add an apostrophe and s after the compound | The Attorney-General’s office |
| Plural compound noun | Add an apostrophe and s after the compound | The Attorneys-General’s meeting |
Possessive pronouns (determiners)
You don’t need an apostrophe with possessive pronouns. Although the term ‘possessive pronoun’ is commonly used, these types of words are no longer classed as pronouns. They are determiners.
Example
- This is your office. That is theirs.
- The fault is ours.
- Put the report in its place.
Australian place names
Don’t use an apostrophe for Australian place names involving possessives.
Example
- Kings Cross
- Mrs Macquaries Chair
Descriptive phrases don’t need apostrophes
Some nouns are descriptive rather than possessive. Don’t use an apostrophe for these nouns.
Example
- workers compensation [A type of compensation for workers]
- visitors book [A book used by visitors]
Use the apostrophe to show possession.
Example
- They signed the visitors book. [Descriptive: a type of book]
- She attended a directors meeting. [Descriptive: a type of meeting for directors]
- Her visitor’s book was lying on the table. [Possessive: the book her visitor owns]
- The director’s office was refurbished. [Possessive: the office where the director works]
Noun phrases about time don’t need apostrophes because they’re descriptive, not possessive.
Example
- 6 weeks time
- 3 months wages
When the time reference is in the singular, use an apostrophe to show the noun is singular.
Example
- a day’s work
- the year’s cycle
Apostrophes show contractions
Apostrophes show that you have omitted letters in contractions.
Example
- I haven’t seen the report.
- It’s a busy day at the office.
Don’t confuse ‘it’s’ (the contraction of ‘it is’ or ‘it has’) with ‘its’ (to show that ‘it’ owns something).
If you can divide ‘it’s’ into ‘it is’ or ‘it has’, then you need to use an apostrophe. ‘Its’ is a possessive pronoun and doesn’t have an apostrophe.
Example
- It’s time to give the committee its terms of reference.
Plural nouns don’t have apostrophes
No apostrophe is needed for the plural form of a noun. This type of error is known as the ‘greengrocer’s apostrophe’.
Correct
- the 2020s
- committee reports
- newer 747s
- fresh avocados
Incorrect
- the 2020’s
- committee report’s
- newer 747’s
- fresh avocado’s
Single letter and digit plurals
There are exceptions to the rule of not using an apostrophe for the plural form of a noun.
Use an apostrophe for plurals of single letters and single-digit numbers. These have an apostrophe before the ‘s’.
Example
- Binary code uses 0’s and 1’s.
- Dot your i’s and cross your t’s when you edit the report.
Plurals that are not usually nouns
Apostrophes show plurals of words that are not usually nouns.
Example
- He was a good speaker. He never used ‘um’s’ and ‘er’s’ when addressing his staff.
- Don’t use ‘like’s’ and ‘you know’s’ when speaking to your manager.
Apostrophes can stand in for sounds
Apostrophes show sounds in words from other languages.
Example
- She was reading the Qur’an.
- Ge’ez is an ancient language from Ethiopia.
Some official names have apostrophes
Use the apostrophe only when it forms part of the official name of an organisation.
Example
- National Farmers’ Federation
- Australian Workers Union
Release notes
The digital edition consolidates information about apostrophes and provides illustrative examples to help users understand correct use.
The sixth edition had information about apostrophes in several sections.
The Content Guide had brief advice about using apostrophes.
About this page
References
Dixon JC and Bolitho B (2005–2019) Course notes and exercises: editing and proofreading for the workplace, Centre for Continuing Education, Australian National University, Canberra.
Murphy EM with Cadman H (2014) Effective writing: plain English at work, 2nd edition, Lacuna, 2014.
Seely J (2001) Oxford everyday grammar, Oxford Paperback Reference.
Stilman S (2004) Grammatically correct, Writer’s Digest Books, 2004; revised and updated, 2010.
Strunk W and White EB (2000) The elements of style, 4th edn, Longman, New York.
Truss L (2003) Eats, shoots and leaves: the zero tolerance approach to punctuation, Profile Books, London, 2003.
University of Chicago (2017) ‘6.115: ‘‘smart’’ apostrophes’, Chicago manual of style, 17th edn, University of Chicago Press, Chicago.