You don't have to wander very far on the Internet before you encounter examples of apostrophes being used in entirely the wrong way. Here's a basic guide to making sure you're not responsible for howlers like "The problem with it's design is that it let's you send a message too easily".
Why we're confused
The main reason apostrophes are a problem in English is because they serve two essentially separate purposes:
- Indicating missing letters: it's being short for it is, don't being short for do not. Most often the apostrophe indicates a single missing letter, but there can be more than one omitted (I've being short for I have). These structures are often referred to as contractions.
- Indicating ownership: The dog's tongue, the nuns' suitcases. More properly known as the possessive apostrophe.
I realise that if you were logically and historically minded, you could argue that the apostrophe does in fact serve the purpose of covering for missing letters in both cases: the dog's tongue can be seen as short for the tongue of the dog. But that's probably not going to help you get it right. It's much more helpful to remember that there are two different uses for the apostrophe -- ownership or omission, if you want a handy version starting with the same letter -- and to think through which of them applies whenever you are unsure.
Its and it's
That rule is especially important in the case that seems to cause the most confusion: its versus it's. In the case, the version without an apostrophe is the one that indicates ownership: The cat licked its fur. It's is a contraction, most commonly short for it is, but also used for it has. (I would advise against the latter use, but that's not to say it isn't common.)
A lot of people seem to have absorbed the idea that apostrophes are always used for ownership, and hence proceed to write inaccurate phrases like "One of it's main problems". This is why you can't reduce apostrophe usage to one simple rule. In the case of it's, you need to remember that the apostrophe means there's something missing, not that someone owns something. More directly: if the sentence you're writing doesn't make sense if you expand it's to either "it is" or "it has", then the apostrophe is not needed.
Strategies for dealing with apostrophes
Like most matters to do with spelling and grammar, practice makes perfect. Beyond memorising the it's/its distinction, here are the key basic principles to remember. (Picture by pondspider)
Don't use apostrophes in plurals This is the so-called greengrocers' apostrophe -- randomly added to words where there's nothing missing and no ownership is implied.
Proof everything you write. Mistakes often happen because people don't look back over what they've written and see if it is accurate. Proofing your work will pick up many more errors than just apostrophe problems, but going back and expanding out contractions to see if they make sense is a good start.
Don't trust technology. Auto-correction systems help us avoid ridiculous typos, but they have two disadvantages: they mean that we're less likely to form the habit of correcting and check our own work, and sometimes they're just flat-out wrong. iOS, for instance, always automatically expands its to it's, even though the latter is frequently incorrect. (It also pulls a similar trick with lets, which is just as annoying). It's a pain to have to manually correct these kinds of errors, but if you don't, you will be wrong. (For what it's worth, a while back I emailed Steve Jobs to ask if Apple was ever going to fix this bug. I never got a reply.) Picture by Ben Haylock
Be consistent. It's easy to say "I'm only sending a text message, so it doesn't really matter". That's arguably true as far as the individual message goes. However, every time you send a text off with that kind of mistake, you're reinforcing a bad habit. When it comes to something that actually matters -- be that a job application or an email to your boss pushing for a pay rise -- you're much less likely to recognise the error because you've trained yourself to ignore it.
When in doubt, don't use contractions. Especially in work contexts, the best bet may be to avoid using contractions in your writing as much as possible. This isn't a total solution -- some contexts don't demand formal writing and many people won't realise that you're even exists as an alternative. But it's something to consider.
(By the way, I realise there are a bunch of highly specific rules surrounding the use of possessive apostrophes with words ending with an s which we haven't covered here. However, in terms of improving your punctuation performance, getting the absolute basics right is more important.)
What tricks do you use to make sure you deploy apostrophes correctly? It's high time you shared them in the comments.
Lifehacker 101 is a weekly feature covering fundamental techniques that Lifehacker constantly refers to, explaining them step-by-step. Hey, we were all newbies once, right?