What is Included in Square Footage?

Carl, Currently I am looking at building a house as my own contractor. I am still trying to figure out where all of these "PER SQ. FT" prices are coming from and what they mean.

For example, does PRICE PER SQ. FT. include the finished basement.....More

When estimating the cost to build a house if the basement is finished in the same quality as the area above grade and with 2 means of ingress and egress in all habitable areas (excluding baths) then in most locales it can be considered heated living space (area) under roof....More