How are Square foot calculations made?
This is a concern in America that is as old as the country itself.
Currently, there are NO federal or local laws defining the exact methodology for determining this.
Given that methods will vary, comparing homes simply on the basis of reported sq footage could be misleading. DO NOT allow square footage measurements alone to determine your home buying choices.
You can often find obviously smaller homes advertising similar square footage as much larger homes. Sadly, when it comes to house measurements it's a bit of the "wild west".
The method used here is the ANSI standard (American National Standards Institute)