Measurement of Homes
All homes are measure and their square footages calculated using the ANSI Standards. The American National Standards Institute (ANSI) is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States.
Per Fannie Mae: "Appraisers are now required to use the Square Footage-Method for Calculating: ANSI® Z765-2021 (American National Standards Institute ®) measuring standard for measuring, calculating, and reporting above and below grade square footage(s) to determine gross living area (GLA) and non-GLA areas of subject properties for appraisals requiring interior and exterior inspections with effect dates of April 1, 2022 or later on loans sold to Fannie Mae"
"All footprint sketches and floor plans must be computer-generated (not hand-drawn), indicate all the dimensions needed to calculate the above/below grade and finished/unfinished square footage of each level and other areas such as a garage, and show the calculations to demonstrate how the square footage was derived."