Your question is too broad: magnetic levitation is not a subject for a single simple answer.
Try to narrow down your question, possibly after getting a basic knowledge on the subject.

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Thank you for responding, sorry for the vagueness as you can tell I'm not to experienced with magnets. But hopefully this will help. The type of magnet I planed on using was a rare-earth magnet. I want to hold a weight of 100 lb. at a height of 3 cm. There are two side supports to prevent it from moving left and right. I am including a example drawing, hopefully this will be enough information.

• http://files.engineering.com/getfile.aspx?folder=c1f2f265-766a-4a4d-8bfb-4e

First of all, what is your goal here??  Are you trying to attempt some parlor trick?
There are magnets that can do what your talking about, but your schematic is not concise enough for me to tell if you have thought this through.
Also, the object that you are trying to levitate, how large is it?  Not its weight, its
volume.
The magnets that you are talking about are very dangerous and must be handled
with extreme caution, just so you know.