You might think this would have been settled some time ago but apparently not: builders, real estate agents, and assessors do not have a common standard by which to determine the square footage of a house.

Many shoppers blindly trust that the size of a new home featured in an ad or brochure is accurate. But the reality is that no official industry standard exists for calculating residential square footage, nor is there widespread consensus on the correct measuring methodology.

Some builders and agents, for example, tally a home’s total footprint, including uninhabitable space (such as areas between walls), while others round off calculations to the next highest number…

Steve Carr, president of Naperville-based Carr Building and Development LLC, said in new construction the builder or architect usually determines square footage calculations.

For resale homes, square footage is typically determined by the seller’s real estate agent (who will measure the dimensions or obtain predetermined measurements from the county assessor’s office) or by an appraiser, who is enlisted by the seller or, if an appraisal is ordered, the buyer’s lender, Wittman said.

So it sounds like the square footage is determined by whoever has a financial interest in the number. It would be interesting to do a study and look at a sample of homes and see whether the square footage fluctuates depending who is doing the measuring (a buyer, seller, or assessor).

There is some interesting discussion later in the article about how homes cannot strictly be compared on the price per square foot as there are other factors involved. This is true but I think this is misleading: there are few figures that people start with when looking for a home and square footage is one of them (perhaps alongside how many bedrooms the home has). I have thought in the past that people who buy homes for their square footage are different kinds of people (social class, taste) compared to those who buy for the architecture of the home or perhaps the neighborhood.

All together, square footage matters for everyone involved in the building, buying and selling, and taxing of homes and I’m surprised that there is no single standard. Who would lose the most by doing this?