General Rules:

  • Apostrophes are used to show omission, show plurals of single letters and show possession.
  • Never use apostrophes with personal or relative pronouns to show possession (e.g., its, hers, his, theirs, whose, etc.).
    • Correct: The giraffe is tall. Its legs are very long.
    • Incorrect: The lion rolled over on it's back.
  • When using an apostrophe with a pronoun to show possession, make sure you're intending to form a contraction as opposed to the possessive (your vs. you’re, its vs. it’s, whose vs. who’s).
  • Contractions may be used in AP Style, but avoid overusing them. Stick with those that appear in the dictionary and are commonly used in everyday speech and writing.

Show Omission

Omission of letters: An apostrophe notes the omission of letters at the beginning, middle or end of a word.
  • rock ‘n’ roll
  • ne‘er
  • ‘til
Omission of figures: An apostrophe notes the omission of figures in years and decades. Ensure the implied century is obvious within the context.
  • 1920s to ‘20s
  • class of 1978 to class of ‘78

Show Plurals of Letters

Rule: Apostrophes are used to show the plural form of single letters.
  • The student earned four A’s and two B’s.
  • Dot your i’s, and cross your t’s.
Rule: Apostrophes are not used to show plurals of numerals or multi-letter combinations (e.g. 1980s, 2s and 4s, CEOs).

Show Possession

Plural nouns ending in s: Add only the apostrophe to show possession.
  • the girls’ room
  • the horses’ corral
  • the states’ borders
  • the CEOs’ dining area

Plural nouns not ending in s: Add ‘s to show possession.
  • men’s
  • women’s
  • alumni’s

Plural noun forms with a singular meaning: Add only the apostrophe to show possession, but also view the section on inanimate objects below.
  • shingles’ symptoms
  • the news’ headlines

Nouns with the same spelling for singular and plural forms: Treat them as plural nouns even when the meaning is singular. Add ‘s to show possession for those not ending in s, and add only the apostrophe to show possession for those ending in s.

    • the two deer’s antlers
    • the scissors’ handle
    • the two fish’s scales

Rule: For names of entities in plural form, follow the same construction.

  • United States’ security
  • Smith Brothers’ profit

Singular common nouns ending in s: Add ‘s to show possession if the following word does not start with s. If the following word starts with s, use only the apostrophe to show possession.
    • the waitress’s aprons
    • the waitress’ shifts

Singular nouns not ending in s: Add ‘s to show possession.
  • the girl’s room
  • the horse’s corral
  • the state’s borders
  • the CEO’s dining area
Exception: Words ending with an ‘s’ sound that are followed by a word starting with s. In these cases, add only the apostrophe to show possession.
  • appearance’ sake, but appearance's cost
  • conscience’ sake, but conscience's voice

Singular proper names ending in s: Add only the apostrophe to show possession.
  • Mr. Jones’
  • Curtis’ hat

Pronouns: Interrogative and relative pronouns show possession with different forms (yours, ours, mine, its, theirs, his, hers). For other pronouns, follow the applicable rules for nouns.
  • anyone’s guess
  • others’ choices
  • another’s opportunity

Compound words: Using the applicable rules for nouns based on spelling and/or meaning, use the apostrophe on the word closest to the object being possessed.
  • anyone else’s opinion
  • the lieutenant governor’s mansions (one governor)
  • the lieutenant governors’ mansion (more than one governor)

Descriptive phrases: Don’t add an apostrophe to a word ending in s when it’s used descriptively instead of to show possession.
  • a writers cheat sheet
  • Green Bay Packers defensive lineman
Note: To determine if the word is used descriptively, check if the long form of the phrase includes “for” or “by.” If it does, skip the apostrophe.
  • a cheat sheet for writers
  • a defensive lineman for the Green Bay Packers

Inanimate objects: There is no rule against using possessives for inanimate objects, but avoid personifying them too often. Instead, use an “of” construction. For example, the previously mentioned phrases would be better as follows:
  • symptoms of shingles, not shingles’ symptoms
  • the headlines of the news, not the news’ headlines

Joint vs. individual possession: For an object that is owned jointly, use an apostrophe after the last word only. For objects owned individually, use an apostrophe after both words.

   Examples of joint ownership:

  • Sammie and Beth’s office
  • Maggie and Sam’s desk

 

   Examples of individual ownership:

  • Sammie’s and Beth’s offices
  • Maggie’s and Sam’s desks