Writing Center
Apostrophes
Indicating Possession:
To make a singular noun possessive, add ‘s to the end of the word, even if it already ends in s:
Sarah’s cabin; a month’s time; the grass’s color.
To make a plural noun ending in s possessive, add an apostrophe after the s:
the students’ classroom.
Typically, if a word is a singular noun with an s added to the end, it is in the possessive case. A word’s
possessive case is usually thought of in terms of ownership, but it can indicate other relationships as
well:
a student’s school, Jefferson’s birth date, the industry’s failure, this week’s weather.
Since many instances of possession are not very obvious, it can be more helpful to look for clues that a
word may require the possessive apostrophe than to memorize every kind of possession. To determine
whether a noun or noun phrase is possessive and requires an apostrophe, try turning it and the word(s)
following it into an of phrase:
The school of the student (The student’s school)
The birth date of Jefferson (Jefferson’s birth date)
The weather of this week (this week’s weather)
If the resulting of phrase makes sense, then the possessive apostrophe is necessary.
The only possessive nouns that do not take an apostrophe are possessive pronouns (his, hers, its). This
can be confusing, especially in the case of its, which can also appear as the contraction for it is, which
does require an apostrophe:
The robin built its nest in our garage.
It’s already midnight. (It is already midnight.)
If a compound noun is possessive, add the apostrophe only to the last word or piece of the compound:
The prime minister’s hat is fancy and psychedelic.
The police car’s lights were bright.
My father-in-law’s house is enormous.
To indicate joint possession (possession applying collectively to more than one noun), add an
apostrophe to the last noun only:
Have you seen Mary and Leo’s new car? (The same car belongs to both Mary and Leo.)
However, if more than one noun possesses something individually or separately, each noun has its own
apostrophe:
Sam’s and Grace’s work schedules are very different this week. (Sam and Grace each have a
unique schedule).
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Omitted Letters and Numbers:
When letters or numbers are omitted from a word, use an apostrophe to indicate the omission. This is
done in contractions:
Amy doesn’t (does not) have any money.
The dog’s (dog is) angry.
You could’ve (could have) told me that before.
Words are also shortened when not part of a contraction, often for stylistic or colloquial applications:
I’m goin’ home (going).
He was born in the ‘60s (1960s).
Denoting Certain Plurals
Apostrophes are not normally used to make nouns plural, but they are in certain special situations. It is
generally done in cases where not including the apostrophe could result in confusion about what is
being said or which word is intended. Consider the following example:
I got three A’s and two B’s (individual letters are normally italicized, but academic grades are).
The apostrophe is used here to avoid confusion resulting in A’s being read as as. It is then added to B to
remain consistent and indicate that these two words are connected and in the same category.
Apostrophes are encouraged for pluralizing single lowercase letters, and optional for single uppercase
letters. The apostrophe is not necessary in pluralizing abbreviations written as words:
Mind your p’s and q’s.
We have three TVs.
Know the dos and don’ts of apostrophe use.
Avoiding common mistakes:
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Remember that the word its only takes an apostrophe when it is used as a contraction for it is.
Except in the special cases mentioned above, plural nouns do not require apostrophes:
Incorrect: The test covered three chapter’s from our textbook.
Correct: The test covered three chapters from our textbook.