Bengaluru Flats: Advertised Size vs RERA Carpet Area

A "1,500 sq ft" flat in Bengaluru usually has about 1,000 sq ft you can actually carpet. That is not a guess: it is what happens when you set the size a project is advertised at against the carpet area the builder filed with the Karnataka Real Estate Regulatory Authority (RERA) for the same unit type.

We did that for every residential project registered in Bengaluru Urban district that we could match to a listing, and separately worked out how big new flats are according to RERA filings alone.

The short answer

• Across 646 like-for-like comparisons in about 520 projects, the advertised size was a median 1.50 times the RERA carpet area. Half of all cases fell between 1.35× and 1.64×.
• The ratio barely changes with size: 1, 2, 3 and 4 BHK all come out at 1.50–1.51×.
• A typical new 2 BHK has 777 sq ft of carpet area and a typical 3 BHK 1,095 sq ft, according to 3,135 residential RERA registrations.

Why the two numbers differ

Since 2017, RERA requires projects to be sold on carpet area: the usable floor inside the flat's walls, excluding external walls, service shafts and the balcony or verandah. Most listings and brochures still quote super built-up area, which adds a share of lobbies, lift cores, staircases, the clubhouse and other common areas, plus the walls and balconies. Neither number is wrong, but they measure different things, and the gap between them — the "loading" — is what you pay for without being able to use.

Part of the 1.50× is balconies, which RERA records separately from carpet area. A project with large balconies will show a bigger gap without any more common-area loading.

How big new Bengaluru flats are, by RERA filings

Configuration	Median carpet area	Middle half of projects	Registrations
1 BHK	441 sq ft	345–533 sq ft	302
2 BHK	777 sq ft	699–879 sq ft	948
3 BHK	1,095 sq ft	953–1,259 sq ft	1,126
4 BHK	1,863 sq ft	1,612–2,416 sq ft	333

By taluk, the typical 2 BHK and 3 BHK carpet areas are:

Taluk	2 BHK	3 BHK
Anekal	761 sq ft	1,031 sq ft
Bengaluru East	784 sq ft	1,077 sq ft
Bengaluru North	764 sq ft	1,098 sq ft
Bengaluru South	793 sq ft	1,137 sq ft
Yelahanka	807 sq ft	1,173 sq ft

Anekal (Electronic City, Attibele, Chandapura) has the most compact homes; Yelahanka and Bengaluru South the most generous.

Advertised size over RERA carpet area, by configuration

Configuration	Median ratio	Comparisons
1 BHK	1.51×	37
2 BHK	1.50×	165
3 BHK	1.50×	337
4 BHK	1.51×	81

What to do with this before you book

• Ask for the carpet area in writing, per unit, and compare prices per sq ft of carpet — not per sq ft of super built-up. A flat at ₹9,000 per super built-up sq ft costs about ₹13,500 per sq ft of carpet at a 1.5× loading.
• Check the RERA registration yourself. Search the project on rera.karnataka.gov.in; the "Bifurcation of Type of Inventories" table lists every unit type with its carpet area. Every Housystan project page that we have matched to RERA now shows those figures under "RERA Karnataka registration".
• Compare loading between projects, not just prices. Two flats advertised at 1,500 sq ft can differ by 150 sq ft or more of usable space.
• Do not rely on the status field alone. Many older registrations still say "Ongoing" years after their completion date because the record was never closed — ask for the occupancy certificate.

How we worked this out

We read the public registration page of all 4,074 approved projects in Bengaluru Urban district on rera.karnataka.gov.in in September 2026, and used the 3,135 residential ones. Builders fill in the unit table inconsistently — some enter each row's total carpet area, some the area of one unit — so for each project we took whichever reading adds up to the project's declared total carpet area, and discarded implausible values (under 15 or over 1,500 square metres per unit) rather than guess. Areas were converted at 10.7639 sq ft per square metre.

For the ratio, we matched Housystan listings to their RERA registration by registration number, or by exact project name and the same builder where the location did not contradict it, and compared each advertised unit size with the median RERA carpet area of the same configuration in that project. Pairs outside 0.8–2.2× were treated as data errors and left out. Advertised sizes are those on the listings, which mostly quote super built-up area.

Source: Housystan analysis of RERA Karnataka public registrations, Bengaluru Urban, September 2026.

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