The Real Estate (Regulation and Development) Act, 2016 gives this exact definition in section 2(k), the only one of the three area terms that the law defines precisely. For a renter, it is the number closest to what you will really live in, and it is almost always smaller than whatever figure is printed on a brochure or a listing. When we quote a home's size, we ask for the carpet area, not just the number on the listing.
The number
Carpet area is defined precisely in law (RERA Act, 2016, section 2(k)); no fixed ratio to built-up or super built-up area exists.
Sources
Where it comes from. Level 1 is a government or court page, level 2 established press, level 3 a portal's explainer, which gives only what is commonly quoted.
- Real Estate (Regulation and Development) Act, 2016, section 2(k), via RERA Karnataka, https://rera.karnataka.gov.in, level 1