Truth and fiction in real estate square footage

From Zillow blog

An inch is an inch is an inch. Or so you’d think. But when it comes to measuring the square footage of a property, it’s not quite that simple.

I doubt there exists a buyer in the entire world of real estate who hasn’t asked, at one time or another, "What is the square footage?" of a particular property. The fact is, however, that measuring the size of a home isn’t an exact science.