How to Use Apostrophes Correctly
The apostrophe has only two jobs in English: contractions and possession. Yet it is one of the most frequently misused punctuation marks. This guide covers both uses clearly — and explains the mistakes to avoid.
The most misused punctuation mark in English
The apostrophe has exactly two uses in English: contractions and possession. That's it. Most apostrophe errors come from using it for plurals — which is never correct — or confusing possession with contraction.
1Contractions — showing a missing letter
An apostrophe replaces missing letters when two words are joined.
| Full form | Contraction | Full form | Contraction |
|---|---|---|---|
| I am | I'm | do not | don't |
| he is / he has | he's | does not | doesn't |
| it is / it has | it's | did not | didn't |
| they are | they're | will not | won't |
| we have | we've | I would | I'd |
| she would | she'd | you are | you're |
Contractions are standard in speech and informal writing. In formal academic writing, write out the full form: do not rather than don't.
2Possession — showing something belongs to someone
To show possession, add 's to the owner.
| Situation | Rule | Example |
|---|---|---|
| Singular noun | Add 's | the dog's lead, James's book |
| Plural noun ending in s | Add ' only | the students' work, the dogs' leads |
| Plural noun not ending in s | Add 's | the children's room, the men's team |
| Two owners (joint possession) | Add 's to last name only | Tom and Sarah's house |
| Two owners (separate possession) | Add 's to each name | Tom's and Sarah's cars |
Names ending in s: Both James's and James' are acceptable. Most modern style guides (including the Oxford Style Guide) recommend James's.
3NEVER use an apostrophe for plurals
This is the single most common apostrophe error in English — sometimes called the 'greengrocer's apostrophe' (after signs reading apple's 50p).
apple's, banana's, the 1990's, DVD's
apples, bananas, the 1990s, DVDs
Quick test before adding an apostrophe: Is something missing (contraction)? Does something belong to someone (possession)? If neither, no apostrophe.
4Its vs it's — the most common apostrophe error
The company released it's annual report.
The company released its annual report.
Its going to be a long day.
It's going to be a long day.
The substitution test: Replace the word with it is. If the sentence still makes sense → it's. If not → its.