Different types of areas are as follows: 

Floor area: 

•  The floor area of the building is the total area of the floor in between walls and consists of the floor of all rooms verandahs, corridors, etc. 

•   The floor area is equal to the plinth area minus the area occupied by walls.  Following are not included in the floor area of the building: 

•   Sills of doors and openings are not included in the floor area of the building. 

•   Area occupied by walls, pillars, and any other intermediate support. 

Plinth area: 

•    It is the covered built-up area measured at the floor level of any storey or at the floor level of the basement. The plinth area is also called a built-up area and is the entire area occupied by the building   including internal and external walls. It is generally 10-20% more than the carpet area. 

Carpet area: 

•  It is a useful area or liveable area or lettable area. It is the total floor area minus the circulation area, verandahs, corridors, passages, staircase, lifts, entrance hall, etc., and minus other non-useable  areas as sanitary accommodations, air conditioning room, etc. 

Circulation area: 

1.        Vertical circulation area of the building is the area or space occupied by staircases, lifts, and the entrance halls adjacent to them which are required for the vertical movement of the users of the building. It may be taken as 4 to 5% of the plinth area of the building. 

2.        Horizontal circulation area of a building in the area of the verandahs, passages, corridors, balconies, porches, etc. which is required for the horizontal movement of the users of the building. May be taken as 10 to 15% of the plinth area of the building