Possessive Pronouns vs Determiners

You hand in a piece of homework you're rather pleased with, and it comes back with a small red circle around one word. "That pencil case is my." Circled. No explanation, just a note in the margin: check this.

Or you're texting a friend — "Whose coming to the park later?" — and they reply, unhelpfully, "who's, you numpty." Or you're reading through your own story before you hand it in and you freeze on a sentence: the dog wagged its tail. Its? It's? Your hand hovers over the keyboard.

Here's the thing. None of this is because you're not clever enough, or because you weren't paying attention in Year 7. It's because a handful of very short, very similar-looking words are quietly doing two completely different jobs — and almost nobody ever sits you down and shows you which job is which. Teachers circle the mistake. They rarely explain the machinery underneath it.

That's what we're doing here. We're going to sort mine from my, and then use exactly the same thinking to crack open the big four traps that catch out even strong writers: its/it's, whose/who's, your/you're, and their/there/they're.

Before you read on, here's where we're heading. By the end of this article, you'll be able to: - Tell a possessive pronoun (mine, yours, his, hers, ours, theirs) apart from a possessive determiner (my, your, his, her, its, our, their). - Use a quick test to choose the right one without guessing. - Fix the its/it's and whose/who's traps for good — plus the closely related your/you're and their/there/they're. - Spot exactly when a small word needs an apostrophe, and when it absolutely mustn't have one.

Beginner (Foundation)

Let's start with the two families, because once you can see them clearly, everything else in this article gets easier.

Possessive determiners sit in front of a noun and tell you who owns the thing that comes next:

my pencil, your homework, his jacket, her phone, its lid, our classroom, their teacher

Possessive pronouns stand alone — no noun needed, because it's already clear from context what's being talked about:

mine, yours, his, hers, ours, theirs

• "That pencil case is mine." (= my pencil case)
• "Is that bag yours?" (= your bag)
• "The red hoodie is hers." (= her hoodie)
• "These seats are ours." (= our seats)
• "The sandwiches are theirs." (= their sandwiches)

Notice the pattern? Same ownership, two different jobs. The determiner sits glued to a noun. The pronoun has already swallowed the noun and stands there quite happily on its own.

Here's the test, and it works almost every time: does the word need a noun stuck to it, or can it stand there and finish the sentence by itself?

• "This is my ___" — needs a noun. My what? → determiner.
• "This is mine." — complete. Nothing missing. → pronoun.

Try it the wrong way round and you'll hear it instantly:

• "This pencil case is my." ❌ (Unfinished. My what?)
• "This is mine pencil case." ❌ (You've glued a pronoun to a noun — it doesn't work that way.)

One more thing worth knowing at this stage: its is the odd one out in this family. Every other word has a matching stand-alone pronoun — her/hers, our/ours, their/theirs — but its doesn't. You'd never say "That collar is its." English just doesn't do that. If you need to make ownership stand alone for something referred to as it, you rephrase: "That's its collar," or you name the owner directly: "That's the dog's."

Common Mistake: Writing "That book is her" when you mean "That book is hers." Her is a determiner — it always wants a noun after it (her book). Standing alone, you need the pronoun hers.

Pro-Tip: Try swapping the determiner-plus-noun for the pronoun and see if the sentence still makes sense: "This is my book" ↔ "This book is mine." If both versions work, you've correctly matched the pair.

Quick recap: - Possessive pronouns (mine, yours, his, hers, ours, theirs) stand alone. - Possessive determiners (my, your, his, her, its, our, their) sit before a noun. - Test it: does the word need a noun glued to it? Determiner. Does it sound complete alone? Pronoun. - Its has no stand-alone pronoun partner — English just doesn't use it that way.

Intermediate (Development)

Now let's connect all of that to the words that actually cause the trouble in your exercise books: its/it's, whose/who's, your/you're, and their/there/they're.

These four pairs aren't really about pronouns versus determiners any more. They're about possession versus contraction — a contraction being two words squashed into one, with an apostrophe standing in for the letters that got dropped. Once you know that, the whole family of traps collapses into one single test, used four times over.

its vs it's

This is the one teachers circle most, and spellcheckers are famously useless at catching it, because both words are spelled correctly — just for the wrong sentence.

• its (no apostrophe) = possessive determiner, exactly like my, your, her. "The dog wagged its tail."
• it's (with apostrophe) = a squashed version of it is or it has. "It's raining." (It is raining.) "It's been ages." (It has been ages.)

The apostrophe in it's never means ownership. It means letters are missing.

The test: try expanding the word to "it is" or "it has." If that still makes sense, you want the apostrophe. If it turns into nonsense, you don't.

• "The dog wagged it's tail." → "The dog wagged it is tail." Nonsense. So: its.
• "I think it's going to snow." → "I think it is going to snow." Works fine. So: it's.

whose vs who's

Exactly the same idea, different pair.

• whose = possession — belonging to which person. "Whose bag is this?"
• who's = a squashed version of who is or who has. "Who's coming to football?" (Who is coming?) "Who's eaten my crisps?" (Who has eaten my crisps?)

Test: expand it. "Do you know whose phone this is?" → "Do you know who is phone this is?" Nonsense — so it must stay as whose. "Who's finished their homework?" → "Who has finished their homework?" Fine — so who's is correct.

The companions: your/you're and their/there/they're

These two work on the same expand-and-check logic, so it's worth learning them alongside the big two.

your vs you're - your = possession ("Is that your coat?") - you're = you are ("You're going to love this.") Test: "You're late" → "You are late." ✓

their vs there vs they're This one has a third option thrown in, just to keep you honest. - their = possession ("That's their house.") - there = a place, or "there is/are" ("Put it over there." "There are three cats outside.") - they're = they are ("They're coming at six.")

Ask yourself three quick questions in order: Am I talking about a place? Use there. Am I saying "they are"? Use they're. Does something belong to them? Use their.

Pro-Tip: Whenever you spot an apostrophe sitting in one of these small words — it's, who's, you're, they're — your first instinct should be: "is this hiding missing letters?" If the answer's yes, you're looking at a contraction, not a possessive.

Common Mistake: "The company increased it's profits." Test: "increased it is profits" — doesn't work. Should be its profits.

Quick recap: - its = possession; it's = it is / it has. - whose = possession; who's = who is / who has. - your = possession; you're = you are. - their = possession; there = place; they're = they are. - Expanding the word to check whether "is/are/has" fits is the test that solves all four traps.

Advanced (Mastery)

You've got the mechanics now. This is where we look at the fussier corners — the bits that catch out even confident writers.

Where pronouns and determiners can and can't go

Determiners always sit directly before a noun and can't be doubled up with another determiner:

• "the my keys" ❌
• "a her jacket" ❌

Possessive pronouns, on the other hand, can do the job of an entire noun phrase — including appearing after the word "of":

• "She's a friend of mine."
• "That mistake wasn't his to fix."

Notice: it's "a friend of mine," never "a friend of my." After "of," English always wants the pronoun form, because there's no noun following it for a determiner to attach to.

The asymmetry of his

Most of this family splits cleanly into two different forms — determiner and pronoun. Her/hers. Your/yours. Their/theirs. Our/ours. But his does both jobs without ever changing its spelling:

• "That's his jacket." (determiner)
• "The jacket is his." (pronoun)

It's one of those small oddities of English — no deep logic, just how the language settled.

Why its never takes an apostrophe

This genuinely puzzles a lot of people, because everywhere else in English, possession usually does get an apostrophe: the dog's tail, the teacher's desk. So why doesn't its follow suit?

The answer is history rather than logic. Its is a comparatively young word in English — older English often used his for almost everything ("the tree his leaves," oddly enough). When its did settle into the language, spellings varied for a while, including it's used for possession. Eventually, written English drew a clean line: 's on a noun usually shows possession (the cat's whiskers); 's on a pronoun (it's, who's, you're, they're) usually shows a missing letter. Possessive pronouns and determiners — my, mine, his, hers, its, ours, theirs — never take an apostrophe, full stop [US: period]. Not one of them.

If its had kept the apostrophe for possession, we'd have one spelling doing two completely different jobs, which would be chaos every single time you wrote it. Splitting the jobs is genuinely the tidier outcome, even if it looks inconsistent at first glance.

A quirk worth knowing: whose for things, not just people

You might have been taught that whose is only for people. It isn't — standard English uses it for things too, and has done for centuries:

• "A book whose ending surprised everyone."
• "The school whose roof leaked all winter."

Some writers dodge this by saying "the book, the ending of which surprised everyone" — but that's a stylistic choice, not a correction. Whose for things is entirely standard.

Register: formal writing vs texting a mate

In an exam answer or a formal piece of writing, you'll often avoid contractions altogether — not because it's, who's, you're, they're are wrong, but because full forms sound more serious:

• Formal: "It is important to check that your data is accurate and that its source is reliable."
• Informal: "It's important to check that your data is accurate and that its source is reliable."

Both are correct English. One is simply dressed for a different occasion. In dialogue and stories, though, contractions make speech sound natural — nobody in real life says "I do not know who is coming," so don't force your characters to either.

Common Mistake: "That book is her." — Her wants a noun (her book); standing alone, you need hers.

Pro-Tip: Unsure in an exam? Full forms (it is, who is, you are, they are) are never wrong in formal writing. If in doubt, spell it out.

Quick recap: - After "of," always use the pronoun: a friend of mine, never of my. - His is the one word that works as both determiner and pronoun without changing form. - No possessive pronoun or determiner ever takes an apostrophe — history split the jobs between nouns (apostrophe) and pronouns (no apostrophe). - Whose is correct for things as well as people. - Contractions are a style choice, not a correctness issue — full forms are always safe in formal writing.

UK vs US Note

Good news here — this is one of the tidier corners of grammar. Possessive pronouns and determiners work identically in UK and US English: mine/my, yours/your, its/it's, whose/who's — no spelling differences, no rule differences, on either side of the Atlantic. The only thing that changes is terminology: what I've called a full stop here, an American teacher would call a period [US: period]. Otherwise, everything in this article applies exactly the same way whichever English you're learning.

Key Takeaways

• Possessive pronouns (mine, yours, his, hers, ours, theirs) stand alone and replace a whole noun phrase.
• Possessive determiners (my, your, his, her, its, our, their) sit before a noun and can't stand alone.
• its and whose show possession; it's and who's are contractions of is/are/has.
• your/you're and their/there/they're follow the same expand-and-check logic.
• No possessive pronoun or determiner ever takes an apostrophe — not one.
• After "of," use the pronoun form: a friend of mine, never of my.

Check Your Understanding

1. Choose the correct word: a) "Is this (your / you're) pen?" b) "I think (its / it's) going to be sunny later." c) "That blue bike is (her / hers)." d) "Do you know (whose / who's) won the match?" e) "The team lost (its / it's) captain to injury."
2. Fix the sentence: "The dog chased it's tail until it was dizzy."
3. Is the bold word a possessive pronoun or a possessive determiner? a) "That red folder is mine." b) "I can't find my folder." c) "The car with the dent is theirs."
4. Fill the gaps with their / there / they're: a) "I think ___ going to win the tournament." b) "Can you put your shoes over ___?"
5. Choose the correct sentence: "Who's book is this?" or "Whose book is this?"

Answer Key

1. a) your — b) it's (it is) — c) hers — d) who's (who has) — e) its
2. "The dog chased its tail until it was dizzy."
3. a) mine = pronoun — b) my = determiner — c) theirs = pronoun
4. a) they're (they are) — b) there
5. "Whose book is this?"

Related Reading

This article is the home for the its/it's and whose/who's fixes — other articles in this library will mention them briefly and send you here rather than re-explaining. For the topics next door:

• H2.1 — Personal Pronouns (the wider system these possessives belong to)
• H2.2 — Verbs and Contractions (for how words like it's, who's, you're, they're get squashed together in the first place)
• H1.4 — Possessive Nouns and Apostrophes (for the dog's bone, the girls' toilets — a different system from the one covered here, worth reading alongside it)
• H5.5 — Determiners (for the full inventory of determiners and how my/your/its slot into a noun phrase)

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