Built-up area adds the thickness of internal and external walls — and often balconies — to the carpet area. Definitions vary by builder and city, so always ask which elements are included.
Example
From carpet to built-up
A 2 BHK in Bengaluru has 850 sq ft carpet area. Add roughly 85 sq ft for the walls and a 60 sq ft balcony and the builder may quote about 995 sq ft built-up. Another builder may leave the balcony out and quote 935 sq ft. Both numbers describe the same home, which is why the definition behind the figure matters.
Figures are illustrative, not market rates.
Questions about Built-up area
Is built-up area defined by RERA?
No. The RERA Act defines carpet area only, and registered projects must disclose it. Built-up area is a market term with no single legal definition, so builders and brokers may include or exclude balconies, duct areas and wall thickness differently. Always ask what was included.
How much bigger is built-up area than carpet area?
It depends on wall thickness, balconies and how the builder counts them. Treat any rule of thumb with care and ask for the carpet area of the same unit; the difference between the two figures tells you how much of the quoted area you cannot actually use as floor space.
Which area should I compare prices on?
Carpet area, because it is defined in law and disclosed for registered projects. Compare built-up figures only when both sellers count the same elements. Converting every offer to a price per square foot of carpet area makes a resale flat and a new launch comparable.
Sources
See also
Reviewed