Mike, Please clarify: Square foot cost for something should be based on ONLY square foot of the area to be dealt with: wall, floor, ceiling, window opening, etc.

What, exactly, are you asking about?

when estimating painting of a room is the sf cost the size of the room or the sf of the walls to be painted I know doors windows and trim are additional
so if a room is 12 x12 x 8 the sf would be about 530 sf including the ceiling or do you just figure 144 sf for the room size


thanks

Yes, about 530 sf including the ceiling (and minus door and window openings).

4 walls at 12x8 = 96 sf each
ceiling 12x12 = 144 sf