Apostrophes

Rule 1: Contractions & Omitted Letters

Use an apostrophe with a contraction in the place of the omitted letter.

• don’t -> do not
• isn’t -> is not
• You’re right -> You are right
• She’s a great teacher -> She is a great teacher

Rule 2: It’s vs. Its

The only time an apostrophe is used for it’s is when it is a contraction for it is or it has.

“Its” indicates possession but does not require an apostrophe.

• It’s a nice day -> It is a nice day.
• The cat opened its mouth to yawn. -> Indicates possessive (the mouth belongs to the cat), so no apostrophe.

Rule 3: Singular possession

Use an apostrophe before the “s” to show singular possession (something belonging to one person).

Note: Although names ending in s or an s sound are not required to have the second s added in possessive form, it is preferred.

• one woman’s hat
• the actress’s fan
• one child’s candy
• Mr. Jones’s book
•  Texas’s weather
• Ms. Straus’s daughter

Rule 4: Plural possession

To show plural possession, form the plural of the noun and then add the apostrophe.

• two boys’ hats
• all of the actresses’ costumes
• the families’ houses

Rule 5: No substitution for plural

Do not use the apostrophe in place of the plural.

• We visited the Sanchezes in Los Angeles.
• The Changs have two cats and a dog.
• We carried all of the cartons up two flights of stairs.

Rule 6: Singular compound nouns

With a singular compound noun, show possession with apostrophe + s at the end of the word.

• My mother-in-law’s new car.
• The lady-in-waiting’s pillow.

Rule 7: Plural compound nouns

If the compound noun is plural, form the plural first and then use the apostrophe.

• My brothers-in-law’s season tickets
•  Our sons-in-law’s new boat

Rule 8: Apostrophe + s with names

Use the apostrophe + s after the second name if two people possess the same item.

Otherwise, use an apostrophe after each name.

• Cesar and Maribel’s home -> joint ownership
• Cesar’s and Maribel’s job contracts ->​​ separate ownership

Rule 9: Possessive pronouns

Never use an apostrophe with possessive pronouns: his, hers, its, theirs, ours, yours, whose. They already show possession.

• This book is hers, not yours. 

Rule 10:  Capital letters and numbers

The plurals for capital letters and numbers used as nouns are not formed with apostrophes.

Exception: Use apostrophes with capital letters and numbers to clarify meaning.

• She consulted with three M.D.s.
• He said all of his ABCs before he could walk.
• The show is set in the 1990s. / ( or you could use “the ‘90s”)

• Please dot your i’s. -> You don’t mean the word “is” so we need an apostrophe.