Francois, I stand corrected, technically speaking. True, there is a system on the books for measuring square footage but it can only be applied to "perfect houses." So many of our homes in America, especially the owner-built ones prior to 1950, simply do not fit any neat formula, so I will stand by my purely practical position that there is no uniform way to measure square footage, and as one who has been contractor, and taught real estate for 17 years and written three books on these subjects, I know from experience that real estate agents would be in way over their heads to attempt any such measurements. They are begging for a law suit (and as an expert witness from time to time, I can say that they keep ignoring this problem). Yes, I know that the consumer thinks he/she needs to know the square footage of a home, but I find that when you press them they don't know why and they don't really have any idea of the complexity of the situation. If I asked a consumer if there was any substantial difference between a house with 1800 square feet or one with 1920 sqaure feet, they might say that the difference was not substantial, but that is enough to mean that the house has an additional bedroom, which could mean a twenty percent or more difference in price/value. On the other hand, the house with the small footprint could have so many amenities that could make it the more valuable property that we may always end up comparing apples to oranges. There are simply too many variables and too many problems with relying on square footage for any evaluation of real estate value, and so I will continue as a consumer advocate to try to convince my students to pay little attention to these numbers and pay more attention to floor plan, storage, etc. As for hiring someone who can measure square footage accurately, that is an "academic solution," i.e. one that simply is not practical in the average real estate situation. I know many, many appraisers, and I have yet to meet one who has mastered this topic, and we never get their figures until after the fact when they have little meaning. Of course, there is one solution: we could destroy all of the standing houses and from this day forth require that all houses be built in such a manner that there could be no controversy about the square footage...little ticky tacky boxes on little slab floors with no cubby holes, no garages converted to living space, etc.....but somehow I don't think that is any more practical than trying to determne square footage with absoluteness for houses that were not built to meet absolutely perfect guidelines. I hope these comments are accepted in the spirit intended, namely to educate the reader as to what one practitioner considers to be the reality of real estate.