The toilet flange needs to sit above the finished floor. The actual code reads the bottom of the flange sits even with the surface of the finished floor. Flanges should be no more than 1/4 inch thick. Codes require they be protected from horizontal and vertical movement. This is done by bolting them to the floor.
Good Luck
Raymond
Plumbing Prof

OK good, just in time too, I plan on installing the new toilet tonight. Good thing I havent welded the flange to the pipe yet! OK time to get out my rotozip amd make a 5/8" plywood ring!

Set the toilet last night, perfect fit. Thanks for your help.

Existing flange is plastic with wood screws at the perimeter. After removing screws, I am unable to pry up the flange. Is the flange glued to the plastic pipe? Do I need to cut the vertical plastic pipe, replace it with another vertical pipe then glue a new floor flange? Or do I need to just use more force to pry up the flange?

Before someone says

"Flanges should be no more than 1/4 inch thick. Codes"

They should ask which code your using and what materials.

For example if the floor flange is cast brass it be at least 1/8 th inch thick and of cast iron at least 1/4" having A caulking depth not less then 2" and if one was using "hard lead" weighing at least 1 lb 9 oz and a lead alloy of at least 7.75 antimony by weight,

I normally set the floor flange level with the FF

I have a cast iron floor flange connected to a PVC pipe,how do I remove this flange?

How do I get an answer to this question?