The Editor’s Manual
Free learning resource on English grammar, punctuation, usage, and style.
Form the possessive of a plural name by placing an apostrophe after the “s” that makes the plural, as you would for any other plural noun.
“You’re” is the contraction of “you are,” while “your” is the possessive form of “you.” Don’t use “your” to mean “you are.”
Use an apostrophe with possessive nouns (New Year’s Day, Mother’s Day, Presidents’ Day) but not with descriptive terms (Christmas Eve, Human Rights Day).
“It’s” (with the apostrophe) is a contraction of “it is” or “it has.” “Its” (without the apostrophe) is the possessive form of “it.”
“Who’s” is the contraction of “who is” or “who has,” while “whose” is the possessive form of “who.”
Form the possessive of a name ending in “s” by adding either an apostrophe and another “s” or just an apostrophe. Both are acceptable in formal writing.
Possessive forms of nouns (with an apostrophe either before or after an “s”) and pronouns (without an apostrophe) indicate a relationship of belonging.
Use an apostrophe to form a possessive noun (“the cat’s tail”) or a contraction (“don’t”). Only rarely is an apostrophe used to form a plural (“p’s and q’s”).