Apostrophe Rules: The Complete Guide

Contractions, Possession, and the Grocer's Apostrophe

Quick Answer

Apostrophes are for: Contractions (don't, can't) and Possession (Sarah's book).

Never use apostrophes for regular plurals! "Bananas" not "banana's."

Rule 1: Contractions

An apostrophe replaces missing letters in contractions.

  • don't = do not (o removed) ✓
  • can't = cannot (no removed) ✓
  • it's = it is (i removed) ✓
  • they're = they are (a removed) ✓
  • I've = I have (ha removed) ✓

Rule 2: Possession (Singular)

Add 's to show something belongs to someone/something.

  • Sarah's book → the book belongs to Sarah ✓
  • The dog's tail → the tail of the dog ✓
  • James's car → (or James') ✓
  • The company's policy ✓
  • Today's news ✓

Rule 3: Possession (Plural)

For plural nouns ending in S, add just an apostrophe after the S.

  • The dogs' toys → toys of multiple dogs ✓
  • The students' grades ✓
  • My parents' house ✓
  • The teachers' lounge ✓
  • For irregular plurals: children's, women's ✓

Comparison Chart

Use Rule Example
Contraction Replace missing letters don't, can't, it's
Singular possession Add 's Sarah's, the dog's
Plural possession (ends in s) Add ' after the s dogs', students'
Plural possession (irregular) Add 's children's, women's
Regular plurals NO apostrophe! bananas, cars, 1990s

Common Mistakes & How to Avoid Them

❌ Incorrect:

"We sell fresh banana's."

✓ Correct:

"We sell fresh bananas."

Why? Regular plural—no apostrophe! This error is called the "grocer's apostrophe."
❌ Incorrect:

"The dog wagged it's tail."

✓ Correct:

"The dog wagged its tail."

Why? "Its" (no apostrophe) is possessive. "It's" = "it is."
❌ Incorrect:

"The student's failed the test." (for multiple students)

✓ Correct:

"The students failed the test."

Why? Regular plural—no apostrophe. (Unless possessive: "The students' tests.")

Quick Tips

💡 When in Doubt

Ask: Am I showing possession? Am I making a contraction? If neither, no apostrophe.

✅ The Expansion Test

For it's/its: Can you expand to "it is"? If yes, use it's. If no, use its.

Frequently Asked Questions

Is it "1990s" or "1990's"?

"1990s" (no apostrophe) for the decade. "1990's style" if something belongs to 1990. Modern style guides prefer no apostrophe for decades.

What about "James's" vs "James'"?

Both are acceptable. "James's" is more common in modern American English. "James'" is traditional. Be consistent in your writing.

Do I use apostrophe for abbreviations?

For plurals of abbreviations, no apostrophe: "CDs," "URLs," "PDFs." But some style guides accept "CD's" for clarity.

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