The gross floor area (GFA) of a building is the sum of the floor areas of all plan levels of the building. In the DIN 277 standard of 1987, the German Institute for Standardisation defined the calculations for the floor areas of buildings. Floor areas and room volumes are decisive, among other things, for determining the costs of buildings and for comparing buildings.
The construction footprint is the sum of the footprints of the rising components of all plan levels of a structure, e.g. of walls, columns and piers.
The net floor area (NGF) is the sum of the usable floor areas of all plan levels of a structure located between the rising components.
The functional area (FF) is that part of the net floor area that serves to accommodate central operational systems in a structure.
The traffic area (VF) is that part of the net floor area that serves access to the rooms, traffic within the structure and also exiting in an emergency.