How To Use Apostrophes

1. Avoid using an apostrophe to indicate a plural. The incorrect use of an apostrophe to form the plural is called the greengrocer’s apostrophe, since grocers are often the worst (or at least the most visible) offenders. If you have more than one apple, then write apples, not apple’s. If you cannot replace the word with “his” or “their” and if it isn’t a contraction, then an apostrophe should not be used.

• People often forget the rules when a word ends in a vowel, such as the word “photo.” Many people write “photo’s” instead of “photos.”
• Another common error is using an apostrophe to indicate a plural number set. “The low temperature will be in the 40’s” is incorrect. There should be no apostrophe in 40s. Similarly, decades should not have apostrophes unless they are possessing something. Here is an example of correct grammar for a decade: I was born in the 80s. In that example, 80s is a plural number set that does not possess something. Here is a correct example of apostrophe usage for a decade: I really like 80’s fashion. Here, fashion belongs to the decade of 1980, so there is an apostrophe.
• An exception to this use is in the case of making a single letter plural. Therefore, Why are there so many i’s in the word “indivisibility”? is correct. This is simply for clarity reasons, so the reader does not mistake it for the word “is.” However, in modern usage, the preference is to avoid inserting an apostrophe and instead surround the single letter in quotation marks before pluralizing it: Why are there so many “i”s in the word “indivisibility”?
• Similarly, apostrophes can be used when talking about a word (e.g., this list contains a lot of do’s and don’t’s) but quotation marks can make it clearer (“do”s and “don’t”s).

2. Place an apostrophe before the “s” when you are indicating a singular possessive. With few exceptions, this is true even if the name or word ends in “s.”

• “Jacob’s shoes are very cool.” The shoes belong to Jacob (singular: one person).
• “I found the dog’s old bone buried in the backyard.” The bone belongs to the dog (singular: a single dog).

3. Place an apostrophe after the “s” when you are dealing with a possessive plural case. When a noun is pluralized by adding an “s” to the end (e.g., book to books, tree to trees), the apostrophe must be placed at the end of the word to make it possessive (books’, trees’). But if the word can be made plural without an “s” at the end, this rule does not apply; the apostrophe goes before the “s.”

• “Look at all of the sailors’ boats!” The boats belong to the sailors (plural: there is more than one sailor).
• “The children’s dresses were pink and frilly.” The dresses belong to the children, but since the word children is already plural without having to add an “s” at the end, this is an exception.

4. Use apostrophes in contractions. Sometimes, especially in informal writing, apostrophes are used to indicate one or more missing letters. For example, the word “don’t” is short for “do not”; other examples include “isn’t,” “wouldn’t,” and “can’t.” Contractions can also be made with the verbs “is,” “has,” and “have.” For example, we can write “She’s going to school” instead of “She is going to school”; or “He’s lost the game” instead of “He has lost the game.” A similar usage can be found in the notation of calendar years, as in ’07. In this case, the apostrophe appears in the spot where the missing numbers would have been (before the number, not after as in 07′).

5. Be aware of the its/it’s exception. Use an apostrophe with the word “it” only when you want to indicate a contraction for “it is” or “it has.” Its is one of the few words that indicates possession without an apostrophe. For example, “That noise? It’s just the dog eating its bone.” This may seem confusing, but it follows the same pattern as other possessive pronouns: his, hers, its, yours, ours, theirs.

6. Place an apostrophe after the “s” when you are indicating a singular possessive for a person’s name that ends with the letter “s” if the name is more than one syllable. For example, one can refer to a bike that belongs to Charles as “Charles’ bike.” (But see also the Tip below.) However, one should place an apostrophe followed by another “s” if the name is only one syllable long, for example; “Ross’s bike.”

Some Tips:

• For singular names ending in “s,” the Chicago Manual of Style adds an “s” after the apostrophe, as in “Charles’s bike.” If your work or assignment requires you to adhere to one convention or another, then do so. Otherwise, either form is acceptable so long as it is consistent throughout a single piece of written work.
• The Elements of Style by Strunk and White is a very short and handy guide to writing and punctuation. Keep a copy of this book nearby when you’re writing and refer to it if you’re unsure about usage.
• “Apple’s 89¢ a pound,” literally means that “apple” owns “89¢ a pound” (the possessive) or “Apple is 89¢ a pound” (a contraction).
• If you want to write about a party given by Luke and Ashley Smart and all their children, write “the Smarts’ party” (Smarts is a plural, then add the possessive apostrophe).
• If you have trouble applying the rules for a possessive, rephrase the sentence to use “of” and place the apostrophe after the word in question. For instance: “Look at all of the sailors’ boats!” becomes “Look at all of the boats of the sailors” and you can place the apostrophe after “sailors” to make “sailors'”. Or, “The children’s dresses were pink and frilly.” becomes “The dresses of the children…” and so the apostrophe goes after “children” to make “children’s”.
• If ever in doubt, always remember that apostrophes are almost always used in nouns to show possession. Avoid using apostrophes for anything else.

Some Warnings

• Throwing in apostrophes willy-nilly quickly shows that the writer does not understand the rules about possessives, contractions, and plurals. If in doubt, err on the side of leaving out the apostrophe.
• Don’t put an apostrophe within your name on your return address label. If your surname is “Greenwood,” then “The Greenwoods” is correct, while “the Greenwood’s” is incorrect. “The Greenwoods” indicates the residence of more than one person with the surname Greenwood, not some sort of possession.
• Never write “her’s.” Her’s is not a word, just as you would not write “him’s”. Recall that possessive pronouns do not need an apostrophe: his, hers, its, yours, ours, theirs.
• When a word ends in “y,” as in “try,” take extra care when changing the verb form. For example, “try” does not become “try’s”. “Tries” is correct.
• Do not use apostrophes or quotation marks for emphasis. For example, take a billboard that says: Joe Schmo, the “best” realtor in town! It makes the word “best” appear sarcastic and untrue, rather than emphasized.