When do you use an apostrophe?
The uses of apostrophes
The apostrophe has three uses:
1) to form possessives of nouns
2) to show the omission of letters
3) to indicate certain plurals of lowercase letters.
Apostrophes are NOT used for possessive pronouns or for noun
plurals, including acronyms.
How to make a noun possessive: To see if you need to make a
possessive, turn the phrase around and make it an "of the..."
phrase. For example:
the boy's hat = the hat of the boy; three days' journey =
journey of three days
Once you've determined whether you need to make a possessive,
follow these rules to create one.
1. add 's to the singular form of the word (even if it ends in
-s): the owner's car; James's hat
2. add 's to the plural forms that do not end in -s:
the children's game; the geese's honking
3. add ' to the end of plural nouns that end in -s:
houses' roofs; three friends' letters; the Joneses'
4. add 's to the end of compound words:
my brother-in-law's money
5. add 's to the last noun to show joint possession of an
Todd and Anne's apartment
Showing omission of letters: Apostrophes are used in
contractions. A contraction is a word (or set of numbers) in which
one or more letters (or numbers) have been omitted. The apostrophe
shows this omission. Contractions are common in speaking and in
informal writing. To use an apostrophe to create a contraction,
place an apostrophe where the omitted letter(s) would go. Here are
don't = do not
I'm = I am
he'll = he will
who's = who is
shouldn't = should not
didn't = did not
could've= could have (NOT "could of"!)
'60 = 1960
Forming plurals of lowercase letters: Apostrophes are used to
form plurals of letters that appear in lowercase; here the rule
appears to be more typographical than grammatical, e.g. "three ps"
versus "three p's." To form the plural of a lowercase letter, place
's after the letter. There is no need for apostrophes indicating a
plural on capitalized letters, numbers, and symbols (though keep in
mind that some editors, teachers, and professors still prefer
them). Here are some examples:
p's and q's = a phrase indicating politeness, from "mind your
pints and quarts"
Nita's mother constantly stressed minding one's p's and q's.
three Macintosh G4s = three of the Macintosh model G4
There are two G4s currently used in the writing classrom.
many &s = many ampersands
That printed page has too many &s on it.
the 1960s = the years in decade from 1960 to 1969
The 1960s were a time of great social unrest.
Don't use apostrophes for possessive pronouns or for noun
plurals. Apostrophes should not be used with possessive pronouns
because possessive pronouns already show possession -- they don't
need an apostrophe. His, her, its, my, yours, ours are all
I wrote an Apostrophe 101 document for training purposes. The
areas of contention are:
Never, Never, Never, Ever use an apostrophe in a plural.
In Britain this is known as "The Grocer's Apostrophe",
presumably because they used to leave school at twelve to work in
Dad's grocery shop. "Cabbage's 30p/lb", "Carrot's 50p/lb". Certain
words, for instance those that end in 'x',can take "es" as an
indication of plural or can retain the Latin form, e.g. "vertex"
and "vertices". "Vertexes" is fine though. Certain collective nouns
for animal remain the same as the singular, deer, sheep and moose,
for instance. Others modulate, like "tooth/teeth" and
*In the matter of acronyms, although apostrophe-s is incorrect,
it improves readability and is therefore becoming accepted. e.g.
FRC's "Fellows of the Royal College" which means something
different from FRCS "Fellow of the Royal College of Surgeons" .
Pedant that I am, I can let that go by.
Apostrophe - s, unless the word ends in s, in which case just
tack an apostrophe on the end. e.g. "Keeping up with the Jones'"
and not "the Jones's" or "Joneses. "Bill's dogs' vet bills were
An apostrophe can indicate missing letters, e.g. "should've" and
"could've" for "should have" and "could have". And NOT "should of"
or "could of".
The conjugation of verbs
"He wait's for a bus". "Mom go's to the mall". Should be "He
waits for a bus" and "Mom goes to the mall". When stating the verb
forms for those categories of the person that end in 's' you MUST
NOT use an apostrophe.