There are several important things to remember when using apostrophes:

  • Apostrophes can replace missing letters to form a contractions eg/isn’t
  • Apostrophes can show possession eg/ John’s pen
  • Apostrophes are used in time expressions eg/ 2 weeks’ holiday
  • Apostrophes are used in plurals of abbreviations, letters and numbers eg/3’s and 4’s

Remember:  Do not add an apostrophe just because a word ends in 's'. The plural of words ending in vowels are extremely prone to this error.

Video <videos (not video’s)
Patio  <patios (not patio’s)

Apostrophes are not used:

  • to show plurals eg/three cat’s
  • randomly before a letter eg/she like’s books.

Apostrophes used in time expressions
In a temporal, or time, expression, the apostrophe is positioned before the s for single units of time and after the s for multiple units of time.

Examples: I never did a day's work in my life. It was all fun.
2 years' house insurance.

Apostrophes used to replace letters
Explanation: An apostrophe can be used to show that a letter (or letters) is missing from a word. The use of the apostrophe in this case reflects how people speak.

Example: The weather’s bad.

Remember: Only use an apostrophe to replace a letter for informal writing such as an email, blog or text.

The following two contractions can catch you out: it's and you're.  Think about what letter the apostrophe represents in these two examples:

It’s is a contraction of it is
You’re is a contraction of you are (not your)

Common contractions in English  

When an apostrophe replaces a letter, a new word is formed (most often, but not always, from two words originally). The new word is called a contraction.

For example: it is contracts to it's; they would contracts to they'd

Examples of contractions (Word doc)

Remember: Avoid using an apostrophe to replace a missing letter in formal writing such as essays and reports. The expectation is that your writing should be as formal as possible.

You cannot invent your own contractions.