An apostrophe (') is a punctuation mark used to replace a letter (or letters). An apostrophe can also be used to show possession (e.g., dog's nose), but this too is linked to the idea that an apostrophe replaces a letter. You see, in old English, possession was shown by adding es:
  • doges nose, dogses noses.
The apostrophe later replaced the e or the es to reflect how people spoke:
  • dog's nose, dogs' noses.
There are four uses for apostrophes. They are used:
  • To show possession (e.g., one dog's kennel, two dogs' kennel)
  • In time expressions (e.g., a day's pay, two weeks' holiday)
  • In contractions (e.g., can't, isn't, don't)
  • To show an awkward plural, if it helps your readers (e.g., Hawaii has two i's.)
It's worth saying at the outset that the apostrophe is commonly abused. With the exception of the full stop, it's the smallest character you can write, but it's our biggest grammar villain. Our abuse of the apostrophe has given rise to groups such as the Apostrophe Protection Society and the Apostrophe Police and has incited numerous vigilantes armed with paint rollers on poles to stalk the streets correcting bad apostrophes on bill boards and shop signs. So, let's tackle apostrophe abuse up front. Apostrophes are not used:
  • To show normal plurals (e.g., three cat's [wrong], two video's [wrong])
  • Randomly before the letter s (e.g., He like's me. [wrong])

Examples of Apostrophes Used for Possession

An apostrophe can be used to show possession.
  • The dog's kennel
  • The dogs' kennel
  • Wagner's music is better than it sounds. (Writer Mark Twain)
  • I was devastated when they stopped making sailors' pants with bell bottoms. (Actress Katherine Waterston)
The big question is whether to put the apostrophe before or after the s. The basic rule is this: The apostrophe goes before the s for a singular possessor (e.g., one dog's kennel) and after the s when it's more than one possessor (e.g., two dogs' kennel). In these examples, dog and dogs are the possessors. The position of the apostrophe has nothing to do with kennel. The thing being possessed (let's call it the possessee) can be singular or plural. It has no influence whatsoever on where the apostrophe goes.
  • One dog's dinner
  • One dog's dinners
  • Two dogs' dinner
  • Two dogs' dinners
For the rest of this section, we're going to use the terms "possessor" (here, dog or dogs) and "possessee" (here, dinner or dinners). These are not common terms for explaining how to use apostrophes for possession, but they should be, IMHO. (Possessors are really called possessive nouns, and possesses are really the complements of possessive nouns. Yeah, that's why I like possessor and possessee.) The ruling stating that you put your apostrophe before the s for a singular possessor but after for a plural one seems quite straightforward, but there are four quirks.

(Quirk 1) A plural possessor that doesn't end s

With a plural word that doesn't end s (e.g., children, women, people, men), put your apostrophe before the s.
  • children's toys
  • Zeus does not bring all men's plans to fulfilment. (Ancient Greek author Homer)
  • women's hat
  • (In grammar, "possession" does not always mean ownership. This means a hat for women. Similarly, Picasso's painting is a painting by Picasso. He doesn't own it. Sometimes, it's about "possession" in the loosest terms.)
  • men's sizes
  • people's poet

(Quirk 2) A singular possessor that ends s

With a singular word that ends s (e.g., Wales, Moses, Chris Wells), either add ' (just an apostrophe) or 's depending on how you (yes, you personally) pronounce it.
  • Dr Evans' report
  • (This is correct for those who say Dr Evans report.)
  • Dr Evans's report
  • (This is correct for those who say Dr Evansiz report.)
  • Chris Wells' gherkin
  • (This is correct for those who say Chris Wells gherkin.)
  • Chris Wells's gherkin
  • (This is correct for those who say Chris Wellsiz gherkin.) It is a common convention to use just an apostrophe with religious characters. So, opt for versions like Jesus' hands and Moses' beard as opposed to Jesus's hands and Moses's beard.

(Quirk 3) A possessor that's a compound noun

With a compound noun like mother-in-law, add 's to the end, regardless of whether it is singular or plural.
sister-in-law's carsisters-in-law's husbands
colonel-in-chief's arrivalcolonels-in-chief's meeting
maid of honour's bouquetmaids of honour's dresses

(Quirk 4) A possessor comprising two possessors

With a possessor comprising two possessors, apply the apostrophe ruling to both for individual ownership but just the second for joint ownership.
  • Andrew's and Jacob's factories (individual ownership)
  • Andrew and Jacob's factory (joint ownership)
  • India's and Pakistan's problems (individual ownership, i.e., separate problems)
  • India and Pakistan's problems (joint ownership, i.e., common to both)
With the individual ownership construction, it might be unclear whether a plural possessee (factories in the first example) is really plural or whether the possessors possess one each. Without context, readers will assume that Andrew has one factory and Jacob has one factory. Another construction is required if this is not the case. "Andrew's factories and Jacob's factories" is one option.)

Examples of Apostrophes Used in Time Expressions

Apostrophes are used in time expressions (also called temporal expressions) like a day's pay and two weeks' notice.

The big question with these is where to put the apostrophe. The good news is we've already covered it: the apostrophe goes before the s for a single unit of time (e.g., one day's pay) and after the s when it's plural (e.g., two days' pay).
  • I never did a day's work in my life. It was all fun. (American inventor Thomas Edison)
  • If you can fill the unforgiving minute
    with sixty seconds’ worth of distance run,
    yours is the Earth and everything that’s in it,
    and – which is more – you’ll be a man, my son! (Writer and poet Rudyard Kipling)
  • (This is an extract from Kipling's poem "If".)
The vast majority of these expressions are time expressions, but some relate to value and distance too.
  • Lee has eaten a pound's worth of liquorice and 2 pounds' worth of lemon drops.
  • My neighbour is in the Guinness World Records. He has had 44 concussions. He lives very close to me – a stone's throw away, in fact.

Examples of Apostrophes Used to Replace Letters

An apostrophe can be used to replace a letter (or letters) in a word to reflect how we speak. More often than not, this practice will involve merging two words into one (called a contraction).
  • When I was born, I was so surprised I didn't talk for a year and a half. (Comedian Gracie Allen)
  • (Here, didn't is a contraction of did and not. The apostrophe replaces the o in not.)
  • I'd agree, but then we'd both be wrong. (Anon)
  • (Here, I'd is a contraction of I would, and we'd is a contraction of we would. The apostrophe replaces the letters w, o, u and l in would.) Here is a list of common contractions.
    aren'tare not
    couldn'tcould not
    didn'tdid not
    doesn'tdoes not
    don'tdo not
    hadn'thad not
    hasn'thas not
    haven'thave not
    he'dhe had, he would
    he'llhe will, he shall
    he'she is, he has
    I'dI had, I would
    I'llI will, I shall
    I'mI am
    I'veI have
    isn'tis not
    it'sit is, it has
    let'slet us
    mustn'tmust not
    shan'tshall not
    she'dshe had, she would
    she'llshe will, she shall
    she'sshe is, she has
    shouldn'tshould not
    that'sthat is, that has
    there'sthere is, there has
    they'dthey had, they would
    they'llthey will, they shall
    they'rethey are
    they'vethey have
    we'dwe had, we would
    we'rewe are
    we'vewe have
    weren'twere not
    what'llwhat will, what shall
    what'rewhat are
    what'swhat is, what has
    what'vewhat have
    where'swhere is, where has
    who'dwho had, who would
    who'llwho will, who shall
    who'rewho are
    who'swho is, who has
    who'vewho have
    won'twill not
    wouldn'twould not
    you'dyou had, you would
    you'llyou will, you shall
    you'reyou are
    you'veyou have

    Examples of Apostrophes in Awkward Plurals

    The first thing to say about this topic is that apostrophes are not normally used to show plurals, and lots of your readers will hate it if you use an apostrophe for this purpose. However, that said, there are times when it helps to use an apostrophe to show a plural.
    • There are two c's, two o's and two m's in accommodation.
    • There are no a's in definite and definitely.
    • You use too many but's in your writing.
    • Your z's look like 2's.
    • (When text (often a title) needs to be written with all uppercase letters, it is acceptable to use an apostrophe to show a plural.)

    Why Should I Care about Apostrophes?

    Writers can be divided into two groups: those who get apostrophes and those who don't. The former considers the latter to be uneducated. So, if you're flying by the seat of your pants with apostrophes, learn how to use them properly because you are being judged. Fact.

    Here are the key issues related to apostrophes.

    (Issue 1) Be accurate when identifying your possessor.

    Take a second to identify the possessor and then put the apostrophe immediately after it. If you do this, you can ignore all of those quirks about where to place an apostrophe used for possession.
    CategoryWhat are we trying to say?Write it with no apostropheIdentify the possessorPut your apostrophe immediately afterwards
    singular nounball of the dogdogs balldogdog's ball
    plural nounkennel of the dogsdogs kenneldogsdogs' kennel
    plural noun not ending spoet of the peoplepeoples poetpeoplepeople's poet
    singular noun ending semblem of WalesWales emblemWalesWales' emblem
    Let me make this point again using different words. Everything to the left of the apostrophe is the possessor. So, if you identify the possessor accurately (regardless of whether it's singular, plural or ends with whatever) and put your apostrophe next, it will always be correct. Always.
    • Charles Dickens' novel
    • (His name is Charles Dickens. Everything to the left of the apostrophe is the possessor.)
    • John Dicken's profile
    • (This person is John Dicken. Remember, everything to the left of the apostrophe is the possessor.)
    Let's look at our original examples again, perhaps with newly trained eyes.
    • one dog's kennel
    • two dogs' kennel

    (Issue 2) Stick to the rules. Don't use an apostrophe just because your word ends with the letter s.

    Don't add an apostrophe to a word just because the word ends with the letter s. This is a common mistake, and it is a grammatical howler. (In other words, your readers will think you're a bit dim if you keep doing it.)
    • I like pig's. Dog's look up to us. Cat's look down on us. Pig's treat us as equal's. [wrong]
    • (The words in bold are all wrong. This quotation should have no apostrophes.)
    • Tomato's and oregano make it Italian; wine and tarragon make it French; garlic makes it good. [wrong]
    • (This mistake is particularly common when forming the plural of a noun that ends in a vowel, e.g., video's [wrong], banana's [wrong]. It should be tomatoes in this example.)
    • A spoken word is not a sparrow. Once it fly's out, you cannot catch it. [wrong]
    • (This mistake occurs with verbs too. This should be flies.)

    (Issue 3) Stick to the rules. Don't use an apostrophe just because you've written a unit of time in the plural (e.g., hours, days, years)

    Don't use an apostrophe every time you write seconds, minutes, hours, days, weeks, months, etc. Only use an apostrophe where the word of could have been used.
    • a year's insurance (a year of insurance)
    • two weeks' holiday (two weeks of holiday)
    • To me, old age is always 15 years' older than I am. [wrong]
    • (Badly transcribed version of a quotation by the Irish painter Francis Bacon)

    (Issue 4) Don't confuse the contractions it's, you're and they're with its, your and their/there.

    Don't confuse the contractions it's, you're and they're with its, your and their/there. A mistake involving one of these is a howler. You might get away with one slip, but you won't get away with two. Your readers will label you "uneducated". Here's a fool-proof way to avoid making a mistake involving it's, you're or they're: never use them. This tip works because you can always expand them to it is (or it has), you are or they are. So, you don't need to use them at all. Okay, that might have been a bit draconian. So, let’s soften the tip to this: If you can expand your it's, you're or they're to the full version, then it's correct. If you can't, you should be using its, your or their/there. (There's more about its, your and there on the entry for possessive adjectives.)

    (Issue 5) Don't write could of, should of or would of.

    The contractions could've, should've and would've expand to could have, should have and would have. You won't get away with writing could of, should of or would of once…not even once. In fact, if you've ever written could of, should of or would of, I would recommend tracing your steps and fixing it. Invent a time machine if necessary.
    • Could of ironed it. [wrong]
    • (On 8 March 2018, an internet troll posted a picture of a badly creased "International Women's Day" banner with the caption "Could of ironed it". He was slaughtered far more for writing could of than for being sexist.)

    (Issue 6) Think seriously about avoiding an apostrophe that shows an awkward plural

    Using an apostrophe for an awkward plural (regardless how awkward it is) is still unpopular with many people. Therefore, you should expend a few "thinking" calories trying to avoid such an apostrophe. Here are some alternatives for the examples used above.
    • There are two Cs, two Os and two Ms in accommodation.
    • (An alternative for "There are two c's, two o's and two m's in accommodation.")
    • There is no A in definite or definitely.
    • (An alternative for "There are no a's in definite and definitely.")
    • You use "but" too much in your writing.
    • (An alternative for "You use too many but's in your writing.")
    • Your Zs look like 2s.
    • (An alternative for "Your z's look like 2's.")
    • (An alternative for "BUY THREE CD'S FOR THE PRICE OF TWO")
    • It's spelt Hawaii not Hawai.
    • (An alternative for "Hawaii has two i's.")
    If you can't think of an alternative or if the alternative looks too unwieldy, go with the apostrophe version, which is usually the clearest and neatest option…and then fight like a dog if questioned.

    Key Points

    • When using an apostrophe to show possession, everything to the left of the apostrophe is the possessor. That's a 100% rule.
    • Don't shove an apostrophe in a word just because it ends with an s. Stick to the rules. Be particularly vigilant with words that end vowel + s (e.g., bananas, cameras) and with times (e.g., months, years).
    • If can't expand your it's, you're or they're to its full versions (i.e., it is/has, you are or they are), then it's wrong, and you should be using its, your or their/there.
    • Don't write could of, should of or would of…ever.
    • You can use an apostrophe to show an awkward plural, but, out of respect for those who won't like it, have a quick stab at finding an alternative.
    Home Page Mathematics Monster Cyber Definitions Grammar Monster