Carpet area is the usable floor inside an apartment’s walls; built-up area adds the walls and usually balconies; super built-up area adds a share of the building’s common areas. Under India’s RERA law, carpet area is the one with a legal definition — so it’s the only fair basis for comparing two homes.
The three numbers
- Carpet area. RERA (Section 2(k) of the Real Estate (Regulation and Development) Act, 2016) defines it as the net usable floor area of the apartment, excluding external walls, service shafts, exclusive balconies or verandahs and exclusive open terraces, but including internal partition walls.
- Built-up area. Not defined by RERA. Developers usually mean carpet area plus the walls, and often the balconies too. Ask what’s included.
- Super built-up area. Built-up area plus a proportionate share of common areas such as lobbies, staircases, lift wells and sometimes the clubhouse. Also not defined by RERA, and the share (“loading”) varies by project.
Why it matters for a buyer
Two apartments advertised at the same “size” can have very different usable space if one figure is carpet area and the other is super built-up. The same goes for price per square foot: a lower rate on super built-up area can mean a higher rate on what the buyer actually uses.
How to compare fairly
- Ask the developer for the RERA carpet area of each unit type — it must be disclosed.
- Compare carpet area to carpet area, and price per carpet sq ft to price per carpet sq ft.
- List balconies and terraces separately; they’re useful space, just not carpet area.
- If a brochure gives a size without saying which basis it is, say so to the buyer instead of assuming — “basis not stated” is honest; a guess isn’t.
A quick script for clients
“The 2,400 sq ft on the hoarding is super built-up area. The carpet area — the floor you actually live on — is what RERA defines, so I’ve compared all three options on carpet area, and listed balconies separately.”
General information, not legal advice. State RERA rules and individual sale agreements apply.