RERA carpet area is calculated by measuring the net usable floor area inside the apartment, including the space covered by internal partition walls. It excludes external walls, balconies, terraces, service shafts and all common areas such as corridors, lifts and staircases. To understand what is RERA carpet area, simply add the usable floor area of all rooms inside the home. https://www.laxmigroup.co/articles/carpet-area-vs-built-up-vs-super-built-up-area-key-differences-explained/