1. If the singular form of the noun does not end in s or an s sound, add the apostrophe and s (’s).

   Singular		Singular Possessive
   • teacher		teacher’s
   • cousin		cousin’s
   • cat		cat’s

2. If the singular ends in s or an s sound, add the apostrophe (’ ) or the apostrophe and s (’s) if the additional s sound is desired.

   Singular		Singular Possessive
   • glass		glass’ or glass’s
   • bus		bus’ or bus’s
   • fox		fox’ or fox’s

3. If the plural form of the noun does not end in s, add the apostrophe and s (’s).

   Plural		Plural Possessive
   • women		women’s
   • people		people’s
   • alumni		alumni’s

4. If the plural form of the noun ends in s, add only the apostrophe (’ ).

   Plural		Plural Possessive
   • computers		computers’
   • diskettes		diskettes’
   • modems		modems’

5. The possessives of proper nouns are formed in the same way as the possessives of common nouns.  If the singular form of the name does not end in s, add the apostrophe and s (’s).  If the singular ends in s or an s sound, add the apostrophe (’ ) or the apostrophe and s (’s).  The plural possessive always is formed by adding the apostrophe to the plural form.

   Proper Noun		Singular Possessive		Plural		Plural Possessive
   • Phil		Phil’s		Phils		Phils’
   • Ellis		Ellis’ or Ellis’s		Ellises		Ellises’
   • Jones		Jones’ or Jones’s		Joneses		Joneses’
   • Romero		Romero’s		Romeros		Romeros’

6. Certain expressions relating to time, distance, and value also are written with an apostrophe.

   • a moment’s reflection		• four months’ wages
   • one kilometer’s length		• seven miles’ jog
   • a dollar’s cost		• two cents’ worth

7. The singular possessive and the plural possessive of compound nouns are formed by adding the apostrophe to the end of the compound word.

   Singular Possessive		Plural Possessive
   • sister-in-law’s		sisters-in-law’s
   • son-in-law’s		sons-in-law’s

8. Joint ownership is shown by making the last word in the series possessive.  Individual ownership is shown by making both parts possessive.

   • The party was at Mitch and Dave’s place. (joint ownership)
   • I programmed Cheryl’s and Deborah’s computers. (individual ownership)

• somebody’s coat		• everyone’s responsibility
• one’s integrity		• others’ paperwork

1. When showing the possessive of the personal pronoun it, no apostrophe is used.  An apostrophe and s (’s) is used after it to indicate “it is.”

   • I put the book in its place on the shelf. (indicates possessive of it)
   • Those black clouds make me think it’s going to rain. (indicates it is)

   
   

• Carolyn has scored 100’s on all her math tests.
• Your written “o’s” look more like “a’s.”
• In Dar’s report, he used “$’s” to indicate money.
• Don’t forget to include “@’s” in all email addresses.

1. In a context in which the plural is clear, apostrophes after upper-case letters are not necessary.

   • Condi got four As, two Bs, and three Cs.

   
   
2. It is not necessary to use an apostrophe to create the plurals of years, decades, or abbreviations.

   • Most of the scientific discoveries in that area were in the 1990s.
   • All the PhDs in the department received a raise.
   • Sometimes I wonder about the IQs of such gullible people.

   
   

• couldn’t		• he’s		• ’n’
• doesn’t		• it’s		• o’clock
• hasn’t		• let’s		• ’twill
• I was born in ’54.