Apostrophe: Three Uses and Common Mistakes
The apostrophe (’) is a punctuation mark with three uses:
- It appears before or after an s in possessives (cats’ tails, Anita’s books, children’s games).
- It indicates the omission of letters in contractions (cannot → can’t).
- It helps form the plural of a letter, a number, or a word without a standard plural (p’s and q’s, 2’s and 3’s, do’s and don’ts).
In possessives
Use an apostrophe to form the possessive of a noun. With singular nouns and plurals that don’t end in s, insert the apostrophe before the s that indicates the possessive.
- Maya’s cat
- a cat’s whiskers
- the girl’s boots
- a comet’s tail
- the car’s windshield
- Acme Inc.’s profits
- children’s stories
- the alumni’s families
With plural nouns that already end in s, place an apostrophe after the s to mark the possessive.
- The girls’ boots are red.
the boots of more than one girl
- Is that the Murrays’ car parked in our driveway?
With proper nouns (names) that end in s, you may add an apostrophe and another s or just an apostrophe.
- Charles’s pen or Charles’ pen
- Dr. Jones’s car or Dr. Jones’ car
For more discussion and examples, see this article on how to form possessives of names ending in s.
In contractions
Use an apostrophe to indicate the omission of letters or numbers in a contracted form.
- I’ve booked two tickets to Japan. (I have)
- Rita doesn’t believe in mortality. (does not)
- I won’t tell Poco you’re the one who ate his cake. (will not)
- Lulu doesn’t want to ever stop dancing. (does not)
- She just loves dancin’ in the rain. (dancing)
- Maya likes the music of the ’80s. (1990s)
- ’Twas the night before Christmas. (It was)
In plurals
An apostrophe may be used to form the plural of a letter or a numeral to improve readability and avoid confusion.
- There are three a’s in aardvark.
Without the apostrophe, it would not be clear that we are referring to a letter from the alphabet (“three as in aardvark“?).
- Better watch your p’s and q’s at the ceremony.
- What are the five P’s of marketing?
- Will the 2’s and 3’s please stand up? We’ll call the 4’s later.
Some writers also insert an apostrophe in a nonstandard plural.
- The do’s and don’ts are listed in the document.
- In the 1990’s, we lived in a tiny apartment about as big as a large cardboard box.
- I don’t want to hear any if’s and but’s.
However, many style guides (such as the Chicago Manual of Style) now recommend using an apostrophe in a plural only when absolutely necessary to avoid confusion. This guideline is consistent with the sparser punctuation style favored in modern writing.
- All the ifs, buts, and maybes were getting on my nerves.
Omit the apostrophe since doing so doesn’t cause confusion.
- Here is a list of dos and don’ts for your trip to the Amazon.
- I count four ayes and seven nays.
- The late 1990s were exciting times for dot-coms.
Most style guides recommend omitting the apostrophe in plurals of abbreviations consisting of more than one letter.
- Farley’s card never works at any of the ATMs in this city.
- None of the MBAs and PhDs in the room could figure out why the screen wasn’t working, until the janitor came and plugged it back in.
Sometimes, particularly in British English, abbreviations contain internal punctuation. In such cases, inserting an apostrophe makes the plural form more readable.
- None of the M.B.A.’s and Ph.D.’s in the room could figure out why the screen wasn’t working.
See Apostrophes in Plurals for more exceptions and examples.
Common apostrophe mistakes
While you do need an apostrophe to form the possessive of a noun, you don’t need one in a possessive pronoun or determiner like yours and hers.
- Incorrect: Rita flew by yesterday. This cape must be her’s.
Correct: Rita flew by yesterday. This cape must be hers. - Incorrect: This painting of your’s is beautiful.
Correct: This painting of yours is beautiful. - Incorrect: This house is their’s, not our’s.
Correct: This house is theirs, not ours. - Incorrect: The kitten is trying to catch it’s shadow.
Correct: The kitten is trying to catch its shadow.
Writers often use it’s and its incorrectly. It’s with an apostrophe is a contraction; its without the apostrophe is a possessive.
- It’s raining again.
it’s = contraction of “it is”
- This house and all its contents are for sale.
its = possessive (the house’s contents)
Don’t use an apostrophe to form standard plurals of nouns.
- Incorrect: All the pie’s are burned.
Correct: All the pies are burned. - Incorrect: How do mermaid’s moisturize?
Correct: How do mermaids moisturize? - Incorrect: Nesbit tunes piano’s for a living.
Correct: Nesbit tunes pianos for a living.
Don’t use an apostrophe in words such as verbs just because they end in s.
- Incorrect: Poco get’s impatient easily.
Correct: Poco gets impatient easily.