By Jennifer Copley (Last Updated, November 11, 2013)
Apostrophe abuse is common these days (there is an entire blog devoted to shaming the perpetrators of apostrophe offenses; see ApostropheAbuse.com).
The most frequent offenses include confusing possessive forms and contractions, though some people seem to toss apostrophes into words at random.
Here are some simple rules that will keep you from running afoul of the punctuation police.
To show possession with most singular words, add ‘s (this rule applies even to singular words that end in s):
John’s book, Jane’s car, Tim’s attitude, everybody’s things, somebody’s purse, the music’s tempo, the gas’s toxicity, Kris’s homework (some style guides don’t require an extra s after the apostrophe with proper names ending in s; this is an issue of preferred style rather than a universal rule)
To show possession with plural words that don’t end in s, just add ‘s as you would with singular words:
children’s toys, women’s bathroom
When a plural word already ends in s, just add an apostrophe after the s:
the Smiths’ home, the cats’ toys (assuming that multiple cats share the toys), the protesters’ signs
Note: When pluralizing proper names, add es to those that end in s; for example, the plural of Jones is Joneses (indicating a group of people who share the last name Jones); the possessive plural is Joneses’:
The Joneses were a family who lived next door.
The trees in the Joneses’ yard were decorated with beer cans on strings.
When two people own something together, only the second person requires an apostrophe:
Bill and Ted’s apartment, Jack and Jill’s unfortunate hill climbing excursion, Bert and Ernie’s ambiguous relationship
When some or all of what is possessed belongs to each of the individuals separately, both need apostrophes:
Bill’s and Ted’s perplexing hobbies, Jack’s and Jill’s injuries, Bert’s and Ernie’s preferences for romantic partners
Don’t add apostrophes to pronouns such as his, hers, its, theirs, and whose (as in Whose dog ate my hat?).
Time and Money
‘s is often used when referring to time or money.
Ten year’s experience (ten years of experience)
A month’s time
Ten dollars’ worth of candy
An hour’s wait for the doctor
Note: An apostrophe is used in o’clock because this is actually a contraction; o’clock stands for of the clock.
When you’re combining two words, an apostrophe is used to bridge the gap:
- it is = it’s
- they are = they’re
- he is = he’s
- they have = they’ve
- who is = who’s
- had not = hadn’t
- she will = she’ll
- there is = there’s
- what is = what’s
A few contractions take irregular forms (for example: will not = won’t)
Numbers, Letters, and Abbreviations
Most sources recommend against using apostrophes with numbers, references to individual letters, or abbreviations:
1970s is correct (not 1970’s) and ABCs (not ABC’s) is preferred.
However, an apostrophe is used to indicate missing numbers in years, as in the ’70s, which is a shortened version of the 1970s.
A few sources say that using the apostrophe in plural numbers (as in 1970’s) is okay when writing for an American audience. However, most grammar experts object to the practice, so you’re less likely to be scolded or mocked by the punctuation police if you leave the apostrophes out of these plural numbers.
Apostrophes should be added to plurals of individual letters or numbers when they are needed to make the meaning clear, as in the following examples:
Don’t forget to dot your i’s.
One thousand is a number with three 0‘s.
Abstract is a word with two a’s.
Another option is to enclose the letters or numbers in quotation marks or spell out numbers in these cases:
Don’t forget to dot your ‘i’s.
One thousand is a number with three zeros.
Abstract is a word with two ‘a’s.
Many people confuse its (the possessive form) and it’s (a contraction of it is or it has). Apostrophes are used correctly in the following sentences:
It’s a beautiful day. (It is a beautiful day.)
It’s been a long time since we saw her. (It has been a long time since we saw her.)
The roof lost some of its shingles in the storm. (Shingles belonging to the roof were lost.)
Another common mistake is confusing their (which indicates possession) with they’re (which is a contraction of they are):
They’re angry because they lost their place in line. (They are angry because they lost the place in line that belonged to them.)
- Massey University. (2012). Apostrophes. Owll.Massey.ac.nz.
- O’Conner, P. T. (1996). Woe Is I, the Grammarphobe’s Guide to Better English in Plain English. New York, G. P. Putnam’s Sons.
- Oxford Dictionaries. (2013). “Apostrophes.” OxfordDictionaries.com.
- Strauss, J. (2013). “Apostrophes.” GrammarBook.com.
- Trask (1997). “The Apostrophe.” University of Sussex.