Grammar Refresh: When and How to Use an Apostrophe

Apostrophes can be tricky. It’s not always easy to determine when you need an apostrophe, and when you don’t.

For this lesson in grammar, we’ll explore the different uses for apostrophes and some common mistakes to avoid.

1. Apostrophes and possession

Apostrophes are used to indicate possession or ownership.

• For example: My brother’s shoes are orange.

Adding apostrophe + s makes it clear that your brother owns the shoes. This rule is true for most singular nouns and plural nouns that do not end in s.

• Singular noun, possessive
  • The boy’s toy
  • The cat’s tail
  • The building’s foundation

• Plural noun, possessive
  • The children’s playground
  • The women’s bathroom
  • The geese’s pond

Here’s where it can get a little tricky: For plural nouns or words that do end in s, you only need to add an apostrophe to signal possession.

• Plural noun ending in s:
  • The babies’ cribs rocked.
  • The kids’ room was a mess.
  • The siblings’ names all started with A.

For proper nouns that end in s, consult a style guide to determine the appropriate punctuation. The AP Stylebook, used by most American newspapers as well as businesses and other institutions, says that you only need an apostrophe after a proper noun that ends in s.

• Thomas’ train rolled down the hill.
• James’ car broke down.
• Chris’ favorite TV show is “Game of Thrones.”

2. Apostrophes and contractions

Another major use of apostrophes – one that you’ve already seen in this blog post – is contractions. A contraction is when you take two words and combine them through the use of an apostrophe.

• For example: I don’t want to do that.

The apostrophe signifies that you have combined “do not” into one word and takes the place of the missing letter o.

Contractions are often used in casual writing or speech. The use of a contraction can also help you convey a certain tone or accent. For example, the saying “y’all” is a contraction of “you all” and is often used in the American South.

3. Abbreviations and omissions

Apostrophes can also be used to show the omission of letters or numbers. You’ll most commonly see this in dates and mailing addresses, but sometimes they are used in normal sentences as well.

When abbreviating a year, you leave out the first two numbers and replace them with an apostrophe.

• I graduated in ’99.

When you use an apostrophe to omit letters from a normal sentence, this is often an attempt to convey common speech or slang. Sometimes, a grammatically incorrect version of a word is simply how people speak and you want to convey that accurately.

• Helpin’ yourself, are you?
• Can I ask you somethin’?

4. Special cases and exceptions

Plural abbreviations

For the most part, apostrophes do NOT turn a word into its plural form. The only exception is when you have abbreviations that include periods between letters, such as M.D.

• Ph.D. |Ph.D.’s (plural form)
• M.D. | M.D.’s (plural form)

In this case, the apostrophe exists to make the abbreviation easier to read in a plural form.

It’s and its

Another BIG exception is its and it’s. In this case, apostrophe + s does not indicate the possessive form.

It’s is actually a contraction of “it is.” 

• It’s raining outside.
• It’s not too late.
• It’s okay.

Its (with no apostrophe) is the possessive form.

• The street got its name from a prominent politician.
• The trashcan was tipped on its side.
• The dog found its way home.

Keep these apostrophe rules and exceptions in mind next time you write, and don’t hesitate to visit our Writing Center for more one-on-one grammar help!