Apostrophe Rules: The Complete Guide

Reviewed by the Grammarlyzer Editorial Team · Our Review Standards · Published January 22, 2026 · Updated June 13, 2026

Master Contractions, Possession, and Avoid the Most Common Mistakes

Quick Answer

Use apostrophes for:

  • Contractions: don't, can't, it's (it is)
  • Singular possession: Sarah's book, the dog's tail
  • Plural possession: students' grades, the teachers' lounge

Never use apostrophes for: Regular plurals (bananas, CDs, 1990s)

Memory Trick: Apostrophes show missing letters or ownership—never regular plurals.

🔑 Key Takeaway

Apostrophes show missing letters (contractions) or ownership (possession). They NEVER make regular words plural. "Apple's for sale" is always wrong—it's "Apples for sale."

The Three Jobs of an Apostrophe

Every correct apostrophe is doing one of three jobs. If it isn't marking a contraction, possession, or a rare letter-plural, it shouldn't be there.

Job Rule Examples
Contraction marks missing letters do not → don't, it is → it's, they are → they're
Singular possession add 's Sarah's car, the dog's bowl, today's date
Plural possession plural ending in s → add ' only the students' grades, the Joneses' house
Irregular plural possession plural not ending in s → add 's the children's toys, the men's room
Never: regular plurals no apostrophe apples, the 1990s, several CEOs

Common Mistakes

❌ Incorrect:

Fresh apple's for sale.

✓ Correct:

Fresh apples for sale.

A plain plural never takes an apostrophe. This "greengrocer's apostrophe" is the most common sign-writing error in English.
❌ Incorrect:

The company lost it's biggest client.

✓ Correct:

The company lost its biggest client.

"It's" only ever means "it is" or "it has." The possessive "its" has no apostrophe — like his, hers, and theirs.
❌ Incorrect:

The student's all passed the exam.

✓ Correct:

The students all passed the exam.

Here "students" is just a plural subject — no ownership — so no apostrophe. Add one only if something belongs to them: "the students' results."
❌ Incorrect:

We visited the Smith's for dinner.

✓ Correct:

We visited the Smiths for dinner.

To make a family name plural, just add -s (the Smiths). Use an apostrophe only for possession: "the Smiths' house."

🎯 Test Your Knowledge

1. Choose the plural: "Two ___ ran across the field."

2. The ___ playground was repainted.

3. The team celebrated ___ victory.

4. All of the ___ badges were reissued (many employees).

5. The band formed in the ___.

See It Live: Check a Sentence With Our Engine

Try the rule against a real sentence. This widget runs Grammarlyzer's in-browser engine, so nothing you type leaves your device. The starter sentence misuses two apostrophes—fix them, or paste your own.

The correct version is: The cafe sells fresh bagels and the staff love their jobs. Both words are plain plurals, not possessives, so neither takes an apostrophe.

Honest limits: a checker catches broken mechanics, not weak structure. It may pass a technically correct sentence that still reads poorly, so weigh the apostrophe rules guidance above against your own draft.

Frequently Asked Questions

Where does the apostrophe go for a plural possessive like "students"?

When a plural noun already ends in s, the apostrophe goes after the s with no extra letter: "the students' grades," "the teachers' lounge." Irregular plurals that don't end in s take apostrophe + s: "the children's books."

Why doesn't "its" take an apostrophe when it shows possession?

Possessive pronouns (its, his, hers, ours, yours, theirs) never use apostrophes, even though they show ownership. "It's" with an apostrophe is only the contraction of "it is" or "it has."

Is it ever correct to use an apostrophe to make a word plural?

Almost never. Regular plurals, decades, and acronyms take no apostrophe: apples, the 1990s, several CEOs. The one accepted exception is pluralizing single letters for clarity: "mind your p's and q's."

Word Origins & Etymology

Apostrophe comes from Greek 'apostrophos' (accent of turning away), from 'apostrephein' (to turn away). Originally a mark showing omitted letters, it gained a possessive function in English during the 17th century.

English uses apostrophes for two purposes: (1) contractions (don't = do not) and (2) possession (John's book). The confusion arises because possessive pronouns (its, yours, theirs) break the possessive rule by NOT using apostrophes.

🔗 The Connection

The apostrophe is statistically the most misused punctuation mark in English, primarily because of the its/it's confusion and the 'grocer's apostrophe' (apple's for sale).

Real-World Examples

📏 Contraction:

Don't forget to submit the report. (do not)

Apostrophe replaces omitted letters
📏 Possession:

Sarah's presentation was excellent.

Apostrophe + s = belonging to Sarah
📏 Plural Possession:

The students' grades were posted. (multiple students)

Apostrophe after the 's' for plural nouns
⚠️ Irregular Plural:

The children's playground needs repair.

Irregular plurals (children, women, men) add 's — not s'
⚠️ Pronouns:

The dog wagged its tail. (NO apostrophe)

Possessive pronouns NEVER take apostrophes: its, yours, hers, theirs
❌ Grocer's Apostrophe:

Fresh apple's for sale!

Wrong: plural nouns NEVER take apostrophes. It's 'apples' (plural), not 'apple's' (possessive).
❌ Common Mistake:

The Jones's are coming to dinner.

Wrong: for plural family names, add -es with no apostrophe: 'The Joneses.' Use apostrophe only for possession: 'the Joneses' house.'
❌ Common Mistake:

The 1990's were a great decade.

Debatable: AP style says '1990s' (no apostrophe for decades). Some style guides accept '1990's.'
💡 Three Rules:

1. Contractions: apostrophe replaces letters. 2. Possession: 's for singular, s' for plural. 3. Pronouns: NEVER use apostrophes (its, yours, theirs).

These three rules cover 99% of apostrophe usage
💡 The Test:

If you can expand it (it's → it is), it's a contraction → apostrophe. If it shows ownership and isn't a pronoun → apostrophe. Otherwise → no apostrophe.

This decision tree resolves nearly all apostrophe questions

Why Do People Confuse Them?

Apostrophes serve two unrelated functions (contraction AND possession), and then break their own possession rule for pronouns. This triple inconsistency makes them the hardest punctuation mark to master. The 'grocer's apostrophe' (using apostrophes in simple plurals like 'banana's') is so common it became a named phenomenon.

For more practice, see Its vs It's and Your vs You're.

Related Articles

Apostrophe Rules in Real Editing Contexts

In business writing, apostrophe errors are among the most visible grammatical mistakes because they often appear on signs, websites, menus, and marketing materials where they receive constant scrutiny. The "greengrocer's apostrophe" — adding an apostrophe to form a simple plural ("tomato's for sale," "the CEO's have decided") — is so common that it has become a cultural shorthand for grammatical carelessness. In professional documents, misplaced apostrophes in company names, product descriptions, and job titles undermine the impression of organizational competence. Particularly problematic are plural possessives: "the client's needs" (one client) vs. "the clients' needs" (multiple clients) represent different situations, and mixing them up in a service agreement or proposal creates genuine confusion about who is being served and what is being promised.

Academic writing requires consistent, correct apostrophe use because errors signal careless proofreading to reviewers and editors. Possessives of names ending in "s" cause particular uncertainty: "James's argument" or "James' argument"? Chicago style recommends adding 's even to names ending in s: "James's," "Keats's," "Dickens's." AP style also generally adds 's. Some journals and style guides still use only the apostrophe for classical proper names ("Achilles' heel," "Socrates' philosophy") but add 's for modern names. APA style recommends 's for all singular possessives. The key is consistency within a document. Contractions, while generally avoided in formal academic writing, must use apostrophes correctly when they do appear: "it's" (it is) vs. "its" (possessive) represents the most commonly confused pair in academic manuscripts.

When self-editing for apostrophes, work through three specific checks. First, check every word ending in "'s" — is it possessive (correct use) or a simple plural (remove the apostrophe)? "The manager's report" (possessive — correct) vs. "the managers are meeting" (plural — no apostrophe needed). Second, check every contraction for the correct placement: the apostrophe replaces the omitted letter(s), so "don't" (do not), "we're" (we are), "it's" (it is). Third, check plural possessives: if the plural already ends in "s," the apostrophe goes after: "the managers' reports," "the clients' accounts." If the plural is irregular (children, men, women), add apostrophe + s: "the children's program," "the men's conference." These three checks catch the vast majority of apostrophe errors.

Three Uses, Three Checks

Apostrophes serve three functions: (1) possession — "the company's policy"; (2) contractions — "it's" = "it is"; (3) some unusual plurals. They never form regular plurals: "the 1990s" not "the 1990's."

Frequently Asked Questions: Apostrophe Rules

When do I use an apostrophe with "its"?

"It's" (with apostrophe) is always and only the contraction for "it is" or "it has": "It's raining," "It's been a long week." "Its" (no apostrophe) is the possessive pronoun — it shows that something belongs to "it": "The company published its annual report," "The dog wagged its tail." The confusion arises because possessive nouns use apostrophes (the company's report), so writers assume the possessive pronoun does too. But possessive pronouns never use apostrophes in English: its, his, hers, ours, yours, theirs — none take apostrophes. A reliable test: substitute "it is" — if the sentence still makes sense ("It is raining" — yes), use "it's." If "it is" sounds wrong ("The company published it is report" — clearly wrong), use "its."

How do I form the possessive of a name that ends in "s"?

Style guides disagree on this, but most modern guides recommend adding apostrophe + s to all singular names ending in s: "James's," "Thomas's," "the boss's," "Dickens's novels," "Jesus's teachings." The Chicago Manual of Style (16th and 17th editions), AP Stylebook, and APA Publication Manual all recommend this approach for modern names. The alternative — using only an apostrophe without the extra s ("James'") — is acceptable in some style guides and is traditionally used for classical names from antiquity ("Achilles' heel," "Socrates' philosophy"). The key is to follow your style guide consistently. When no guide is specified, apostrophe + s for all singular possessives (including names ending in s) is the safest and most widely accepted choice in contemporary professional and academic writing.

Do decades and abbreviations need apostrophes for plurals?

No — decades and abbreviations form simple plurals without apostrophes. The correct forms are "the 1990s," "the 1920s," "the mid-2000s" — no apostrophe. Similarly, abbreviations and acronyms form plurals without apostrophes: "three CEOs," "several FAQs," "multiple NGOs." An apostrophe in these contexts implies possession or contraction, not plurality. The source of confusion is that apostrophes were once more commonly used for certain plurals in older style guides ("the 1990's," "two CEO's"), but modern guides — including Chicago, AP, and APA — now clearly prohibit the apostrophe for simple plurals of decades and abbreviations. The only exception where an apostrophe aids clarity in plurals is for single letters: "Mind your p's and q's" — without the apostrophe, "ps and qs" looks strange.

How do joint possessives work with apostrophes?

When two or more people jointly own or share something, add the apostrophe + s only to the final name: "Sarah and Tom's project" (they share one project). When each person has their own separate thing, add apostrophe + s to each name: "Sarah's and Tom's projects" (each has their own project). This rule applies to all joint vs. separate possession: "the CEO and CFO's decision" (a joint decision), "the CEO's and CFO's offices" (separate offices). The test: ask whether one thing is jointly possessed or multiple things are separately possessed. Compound nouns also follow this pattern: "my mother-in-law's car" (the apostrophe goes on the final word of the compound noun, not the middle word).

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