Its or it's

'The dog ate its food very quickly.'

Kat asks:
When do you use its instead of it’s?

Hello Kat. Thank you for you question about its and it's. They may have the same pronunciation, but they certainly have different meanings and uses.

First of all, I'll deal with its: I-T-S. This word is a possessive pronoun, as are my, your, his, her, our and their. Look at these examples.

I lost my mobile phone yesterday.
You haven't finished your homework yet.
He visited his parents last weekend.
The dog ate its food very quickly.
Look at that car. Its windows are broken.

So, we use its when we talk about something that belongs to an animal or an object.

With regard to it's, spelt I-T-apostrophe-S, this is actually two words that have been joined together, namely it and is. This is known as a contraction. For example, it's hot today is the contracted form of it is hot today. Here are some other contractions, which all use the apostrophe to join the two words.

I'll is I will
He'd is he would
They've is they have

Importantly, it's is not only the contraction of it and is. It can also be the contraction of it and has, when using the present perfect tense. For example:

It has been raining becomes it's been raining.
It has stopped becomes It's stopped.

It's time for me to end my answer now. I hope you keep using this website, I'm sure you'll agree that its advice is the best available online.

About Gareth Rees

Gareth Rees has a BA (hons) in History and Philosophy of Science, CTEFLA, and DELTA. He has taught EFL, EAP and Business English in China, Spain and England, and he is the co-author of the Language Leader Elementary and Pre-Intermediate English language course books (Pearson Longman). He currently teaches English in the Language Centre at the University of the Arts, London.