Its vs it's: the simple rule and a test you can run in two seconds

The rule: it's is a contraction, its is a possessive

As Purdue OWL puts it, it's is a contraction for "it is" and its is a possessive pronoun meaning "belonging to it". So It's raining out means it is raining out.

Grammarly gives the same split: its shows possession, while it's is a contraction of it is or it has. The apostrophe in it's marks the place where letters were left out (it is becomes it's), and it does not show ownership.

Cambridge Dictionary describes its as a possessive determiner (like my, your, his) that we use when referring to things or animals. In other words, its belongs to the same family as my, your, his and our, and none of those take an apostrophe.

The two-second test: say "it is" or "it has"

The most reliable check comes from several university writing centres. The University of Nevada, Reno advises you to take out the its or it's and replace it with "it is". If the sentence still is grammatically correct, then you can use it's. If not, then its is probably appropriate. Grammarly adds the same idea with "it has": use it's if you can replace the word with it is or it has.

Here is the test at work:

1. ___ a beautiful day. It is a beautiful day makes sense, so write It's.
2. The bird fed ___ chicks. The bird fed it is chicks does not make sense, so write its.
3. ___ been a long week. It has been a long week makes sense, so write It's.
4. The laptop lost ___ charge. The laptop lost it is charge does not work, so write its.

Run the test on every sentence in which you are not sure. It takes two seconds and works in every case, including sentences with long subjects where the mistake is easy to miss.

If you only remember one habit, remember this: when you want to write its, ask whether you can say it is. If you can, add the apostrophe. If you cannot, leave it out.

Why the mistake happens (and why the rule feels backwards)

The confusion has a logical cause. In English, an apostrophe plus s usually shows possession: Maria's car, the teacher's book. So it feels natural to write it's tail for the tail of the dog. The rule for its breaks that pattern.

Purdue OWL gives a simple way to remember it: you don't use an apostrophe for the possessive his or hers, so don't do it with its. The possessive pronouns his, hers, ours, yours, theirs and its all follow the same pattern, and none has an apostrophe.

The pattern has a history too. Merriam-Webster explains that the apostrophe form of the possessive remained extremely common throughout the 17th century. The version without the apostrophe only became dominant in the 18th century, probably because it's was taking on a new role: replacing the contraction 'tis. So the old spelling was once correct, but, as the same article says, the fact that it was right 300 years ago doesn't make it correct today.

There is a second reason: the two words sound exactly the same. As the University of Nevada, Reno notes, the difference between its and it's can be confusing because they are said exactly the same way. Nothing in speech tells you which spelling is needed, so the decision happens only in writing.

How to say it's and its (and when it matters)

In speech, its and it's are the same sound, roughly "itss". That is why nobody can hear an apostrophe error in a conversation. It only appears when you write: in an email, a report, a text message or an exam answer.

Because they sound the same, you can train your ear to use the test in your head. When you hear yourself say "itss" in a sentence, ask which meaning you intend: it is or it has, or belonging to it.

Contractions are normal in spoken English. We say it's much more often than it is, especially in friendly or informal speech: "It's late, let's go." Using the full form (it is) sounds more careful or formal. For more on how contractions sound, see our guide to contractions in English.

As the University of Nevada, Reno writing centre says, in writing it is important to make the distinction. A spelling mistake with its and it's is easy for a reader to spot, and in a job application, a formal email or an exam it can make your writing look careless.

Its and it's in real sentences

Seeing both words in context is the fastest way to learn them. These are all correct.

It's (it is)

• It's a long way to the airport.
• I think it's going to rain.
• It's my birthday on Friday.

It's (it has)

• It's been a pleasure working with you.
• It's got a lovely garden. (British English often says it has got.)

Its (belonging to it)

• The dog wagged its tail.
• Each country has its own traditions.
• Merriam-Webster's example: the sun was so bright, its rays blinded me.
• The company announced its results on Monday.

Notice one more thing: both words can appear in the same sentence. It's clear that the company will lose its biggest client uses it's for "it is" and its for ownership. Test each one separately.

Its works for things, animals and organisations. Cambridge Dictionary shows it with an organisation: he joined the New York Tribune, becoming its editor-in-chief and eventually its principal owner. When you speak about a person, use his, her or their instead.

Common mistakes and the "its'" trap

These are the errors teachers see most often.

• Wrong: The cat licked it's paw.
• Right: The cat licked its paw.
• Wrong: Its a great idea.
• Right: It's a great idea.
• Wrong: Its' (an apostrophe after the s).
• Right: There is no such word. Use its or it's.

Do not mix this up with "could of". Purdue OWL lists the correct contraction: could've = could have, and it warns against "could of". The apostrophe replaces the missing letters, which is the same job it does in it's.

Do not use "its" or "it's" for people. Who's (who is) and whose (belonging to whom) behave in a similar way. Who's coming? uses the contraction. Whose bag is this? shows possession.

Quick quiz: its or it's?

Choose the correct word. Answers follow the list.

1. ___ time to leave.
2. The hotel is famous for ___ view of the sea.
3. I hope ___ going to be sunny.
4. The film has lost ___ magic.
5. ___ been three years since we met.
6. Every language has ___ own rhythm.
7. The company is proud of ___ new office.
8. I think ___ a mistake.

Answers: 1. It's (it is). 2. its. 3. it's (it is). 4. its. 5. It's (it has). 6. its. 7. its. 8. it's (it is).

To practise using both words in speech, try saying each sentence aloud, then rephrase it with the full form: "It is time to leave." This is a good way to check that you understand the meaning. For more ideas on getting speaking practice into your day, read our guide to how to speak English fluently.