This particular post gets a lot of hits. I originally wrote it to try and answer a very specific query — namely, whether phrases like parents’ evening require an apostrophe. However, my guess is that most visitors to this page arrive here because they have a more general question about the use of apostrophes and googled something like ‘Does x need an apostrophe?’ Perhaps that’s you?
Anyway, I have revamped the page to help people out. It now does indeed go through the basic rules about using apostrophes. I hope it answers your question, if that’s what brought you here.
If you do actually want to read more about phrases like parents’ evening and girls’ school and whether or not they need an apostrophe, I have moved the original post to here. I also highly recommend my style guide, which is free for you to read and/or download from here.
We use apostrophes for two reasons:
Apostrophes are NOT needed for simple plurals (more than one of something). You see this mistake time and time again on shop signs and the like. It’s even got a name — the greengrocer’s apostrophe:
a bag of potatoe’s; fish and chip’s; open Monday’s to Saturday’sIncorrect uses of the apostrophe. They are just simple plurals.
We use the apostrophe to denote possession:
The musician’s guitar means ‘the guitar of/belonging to the musician’;
The farmer’s tractor means ‘the tractor of/belonging to the farmer’;
The boss’s pay rise means ‘the pay rise of the boss’.
Note that it doesn’t have to be literal possession. It can just mean ‘of’ or ‘of the’.
The patient’s health problems;
The light’s brilliance.
Most nouns in the plural end in ‘s’ or ‘es’. In these cases the apostrophe comes after the ‘s’.
The musicians’ instruments means ‘the instruments of/belonging to the musicians’;
The patients’ health problems means ‘the health problems of the patients’;
The bosses’ pay rise means ‘the pay rise of the bosses’.
Some plural nouns don’t end in ‘s’. In these cases we treat the apostrophe as we would with a singular noun.
The people’s voice means ‘the voice of the people’.
If someone’s name ends in ‘s’, the convention is to treat it like a plural noun and put the apostrophe after the ‘s’ unless you would make an extra ‘ziz’ sound when saying it aloud. To keep things simple I tend to add the extra ‘s’ most of the time.
Say any of the above aloud and you should hear yourself saying ‘ziz’.
That’s it for the basics. Check out page 11 of my free-to-download style guide for slightly trickier examples.
We use an apostrophe when we shorten words by missing out certain letters.
It’s is short for ‘It is’
We’re is short for ‘We are’
Don’t is short for ‘Do not’
Can’t is short for ‘Cannot’
This may cause a bit of confusion because sometimes we use words with the same spelling but without an apostrophe. For example, as well as it’s we have its. As well as we’re we have were. As well as you’re we have your. There is also a noun cant, which means ‘hypocritical and sanctimonious talk’ and has nothing to do with can’t.
It all depends on the sense in which you are using the word. If you’re shortening two words into one (like I just did then with you’re to mean ‘you are’), use an apostrophe.
It’s a brilliant book is short for ‘It is a brilliant book’;
I bought this book and was amazed by its brilliance means ‘… amazed by the brilliance of it’.
We’re watching the champions is short for ‘We are watching the champions’;
In the phrase ‘The champions were playing’ the word ‘were’ is just the past tense of ‘are’.
The prime minister can’t seem to avoid sanctimonious claptrap and downright lies;
The prime minster can’t seem to avoid indulging in bluff, bluster and cant.