Area Hierarchy — Carpet, Built-Up, Super Built-Up
| Area Type | What it Includes | Relative Size |
|---|---|---|
| Carpet Area | Usable floor area inside flat — measured between inner walls. Excludes wall thickness and common areas | Smallest — 65–75% of super BUA |
| Built-Up Area | Carpet area + wall thickness + balcony/terrace | Medium — ~85–90% of super BUA |
| Super Built-Up Area | Built-up area + proportionate share of all common areas | Largest — used as pricing base pre-RERA |
The loading trap: A builder quoting ₹7,000/sq ft on 1,200 sq ft super BUA = ₹84 lakh. Another quoting ₹9,000/sq ft on 900 sq ft carpet area = ₹81 lakh for the same usable space. Always compare on carpet area basis.
RERA and the Carpet Area Mandate
Since RERA 2016, builders must disclose and price flats on carpet area — not super built-up area. RERA defines carpet area as the net usable floor area of the apartment, including internal partition walls but excluding external walls, service shafts, exclusive balconies, and common areas. If the actual carpet area at possession is less than declared, the buyer is entitled to a proportional price refund.
Related Terms
Frequently Asked Questions
Super built-up area (saleable area) is the total area for which a builder charges — including the flat's built-up area plus a proportionate share of all common areas like lobby, staircases, lift shafts, and corridors. It is always larger than the carpet area you actually use.
Carpet area is the actual usable floor space inside your flat measured between inner walls. Super built-up area includes carpet area plus wall thickness plus proportionate share of all common areas. Carpet area is typically 65–75% of super built-up area. RERA mandates pricing on carpet area.
Loading factor is the percentage by which super built-up area exceeds carpet area. A 30% loading means 1,000 sq ft carpet area = 1,300 sq ft super BUA. Higher loading means more of what you pay for is common area. Older buildings and large amenity complexes tend to have 35–45% loading.
RERA mandates that builders price flats on carpet area basis. Builders can still mention super built-up area for reference, but the legal agreement must use carpet area. Any shortfall in actual carpet area versus declared entitles the buyer to a proportional price reduction.
Use an indicative loading factor of 25–35%: Carpet Area ≈ Super BUA ÷ 1.30 (for 30% loading). For example, 1,300 sq ft super BUA ÷ 1.30 = 1,000 sq ft carpet area. Always ask the builder for the exact RERA carpet area before signing any agreement.