What is the difference between gross living area and square footage?

Square footage is any area measured in square feet. Gross living area is one specific measurement: the finished, above-grade living space of a house, measured to the outside of the exterior walls under ANSI Z765.

When people say a house has a certain square footage, they could mean several numbers. A listing may use tax records that include a basement or garage. A builder may count everything under the roof. A room-by-room total taken inside comes out smaller because it skips the walls.

Gross living area is the version an appraiser uses, and on most loans Fannie Mae buys it has to follow ANSI Z765. It leaves out basements, garages, and unfinished space so that houses can be compared fairly. That is why the appraisal number is often smaller than the listing.