Not eneough info to tell.

It will depend on how thick it's poured, the mix and other environmental factors. I have some leveling compound thats an inch thick that hasn't cracked and a pretty cool look.

As Patricia states...not enough info. The material used, the subfloor it is going over, the thickness of the product and so on and so on...all need to be reported on before we can guess whether or not it will "crack" or not.

Prep is everything. Materials are almost everything. Knowledge level of the person USING materials comes in a close 3rd. And actual install itself all cause a project to "work" or "go wrong".

A single sentance with 8 words in it is not enough for us. Photos of the subfloor and material that you want to use and the skill level of the person doing the work. That's a start.