To use apostrophes correctly in KS3 English, apply them for two jobs only: showing possession ("the dog's bone") and marking missing letters in a contraction ("don't", "it's"). Apostrophes are never used simply to make a word plural — that single confusion is the most common apostrophe mistake examiners penalise.
What are the two jobs of an apostrophe?
An apostrophe has exactly two functions in English, and no others:
- Possession — showing that something belongs to someone or something ("the teacher's desk").
- Contraction — showing that letters have been left out when two words are squashed into one ("do not" becomes "don't").
If a word is not doing either of these two jobs, it does not need an apostrophe — including, crucially, when a word is simply being made plural.
How do you use apostrophes for possession?
The rule for possession depends on whether the owner is singular or plural, and whether the plural already ends in "s".
| Noun type | Rule | Example |
|---|---|---|
| Singular noun | Add 's | the cat's tail; James's book |
| Plural noun ending in s | Add an apostrophe only | the cats' tails; the teachers' lounge |
| Plural noun not ending in s | Add 's | the children's toys; the men's coats |
Notice that a singular name ending in "s", such as James, still takes 's in standard usage — "James's book", not "James' book" — though both forms appear in print and are widely accepted; KS3 and GCSE exam boards accept the 's form as the safer default.
Worked example: "The dogs' owners collected their leads." Here "dogs" is already plural and ends in "s", so the apostrophe goes after the "s" with nothing added, showing the leads belong to more than one dog's owners.
How do you use apostrophes for contractions?
A contraction apostrophe replaces the letters that have been removed when two words are joined into one, and it goes exactly where those letters used to be.
- do not → don't
- it is / it has → it's
- they are → they're
- should not → shouldn't
- I am → I'm
- cannot → can't
- will not → won't
Worked example: "I am not going, because it is too late." becomes, in informal writing, "I'm not going, because it's too late." Each apostrophe sits precisely where letters have been removed — "I'm" replaces the "a" of "am", and "it's" replaces the "i" of "is".
How to check whether you need an apostrophe: a step-by-step method
- Ask: is this word showing something belongs to something else? If yes, it needs a possessive apostrophe.
- Ask: is this word two words squashed into one, with letters missing? If yes, it needs a contraction apostrophe, placed exactly where the missing letters were.
- Ask: am I just making the word plural — more than one? If yes, do not add an apostrophe. Plurals never take an apostrophe on their own.
- If it is possession, check whether the owner is singular or plural, then apply the correct rule from the table above.
- Proofread by reading the sentence aloud. A contraction should be replaceable with its full two-word version without changing the meaning — if it cannot be, you may have used the wrong word entirely.
What is the difference between "its" and "it's"?
This single pair causes more marks lost at GCSE than almost any other punctuation confusion.
"It's" is always a contraction, short for "it is" or "it has". If you cannot expand it back into "it is" or "it has" and have the sentence still make sense, it is the wrong word.
"Its" is a possessive pronoun, meaning "belonging to it" — and like the other possessive pronouns (his, hers, ours, theirs), it never takes an apostrophe.
Worked examples:
- "The dog wagged its tail." — possessive; the tail belongs to the dog. (Test: "the dog wagged it is tail" makes no sense, so "its" is correct.)
- "It's going to rain later." — contraction of "it is". (Test: "it is going to rain later" makes sense, so "it's" is correct.)
Mastering how to use apostrophes correctly KS3 examiners expect takes practice, but the five-step check above makes it manageable.
What are the most common apostrophe mistakes at GCSE?
- The "greengrocer's apostrophe" — adding an apostrophe to a simple plural, such as "apple's for sale" instead of "apples for sale". This is the single most penalised apostrophe error in written GCSE English.
- Confusing its and it's, as explained above.
- Confusing your and you're — "your" is possessive ("your book"); "you're" is short for "you are" ("you're late").
- Missing the apostrophe in a contraction, writing "dont" instead of "don't". Formal GCSE essays are usually better written without contractions at all, but if you use one, punctuate it correctly.
- Adding an apostrophe to a plural possessive that should be singular, or vice versa — for example, writing "the dog's are barking" when there is no possession involved at all; it should simply be "the dogs are barking".
Frequently asked questions
Do you need an apostrophe to make a word plural?
No. Apostrophes are never used simply to show that there is more than one of something — "apples", "teachers", and "books" all take no apostrophe when plural. Adding an apostrophe to a plural (such as "apple's") is a well-known error sometimes called the greengrocer's apostrophe, and it is heavily penalised in GCSE English writing.
How do you make a possessive with a name ending in "s" (e.g. James)?
The standard rule taught at KS3 and accepted by GCSE exam boards is to add 's even when the name already ends in "s": "James's book", "Charles's decision". Some style guides allow just an apostrophe ("James' book") for names ending in "s", but adding 's is the safer, more widely taught default.
What is the difference between "its" and "it's"?
"It's" is always a contraction of "it is" or "it has" — if you can replace it with "it is" or "it has" and the sentence still makes sense, "it's" is correct. "Its" is a possessive pronoun meaning "belonging to it", and like other possessive pronouns such as "his" or "hers", it never takes an apostrophe.
Should you use contractions in GCSE English essays?
In formal analytical essays — such as English Literature responses — it is best to avoid contractions and write "do not" rather than "don't", since formal register is expected. In creative or persuasive writing, contractions are often appropriate for capturing natural speech or an informal, engaging tone, as long as they are punctuated correctly wherever they appear.
For Socratic English grammar practice on punctuation and apostrophe rules, see aitutors.me.