I see these two words confused all the time, even though they’re very easy to get right.

It’s is a contraction for “it is” or even “it has.”

• It’s been a long time since I’ve seen you. (It has…)
• It’s a mistake to buy that property. (It is…)

Its is a pronoun that means something “belongs to it.”

•  I wouldn’t buy that car; its paint job is awful.
• The dog hurt its foot on its walk last night.

If you’re unsure, simply substitute “it is” or “it has” in the sentence to see which version of its/it’s you have. If the substitution works, then you want the version, it’s. If not, then you want its.

It’s simple, right?