One of the most common grammatical errors I run across when editing manuscripts is the misuse of its/it’s. They are easy to confuse, and most people do not even realize there is a difference because the its/it’s differentiation is not an issue stressed in most grade schools. But I am here to tell you there is a difference, and it is easy to know when to use the word or the conjunction once you understand what they each mean.
Its is a adjective. It is used to describe a noun.
Examples: Johnny knocked his cup onto its side.
Alice bought the necklace because she liked its color.
It’s is a contraction. It replaces “it is” in a sentence.
Example: It’s (it is) the yellow one.
Bring a blanket, it’s (it is) cold outside.