The James Dean of the grammar world: "its" vs. "it's"

 

 

When it comes to the possessive form, the word it is a rebel with a clause - the anguished street punk with a heart of gold who loves to cause trouble, and a lot of it, but nothing that can't be worked out.

The trouble it causes has to do with the possessive form vs. the contraction form. In my opinion, it's (it is) in the top three mistakes made  by writers, especially those who don't write often. Heck, even the grammar checker that came with my computer gets it wrong all of the time, telling me to do the opposite of what I should do.

Other singular words form a possessive with the apostrophe-s combination: the boy's ball, Dad's car, the doctor's practice. But the word it is contrary. The possessive is its - with no apostrophe: its food, its length.

The apostrophe comes in with the contraction of it is. The contraction is it's.

So the rules are:
Possessive: its
Contraction for it is: it's