When a builder quotes a price, ask one question before anything else: which area is this priced on? The same flat can be marketed as 1,200 sq ft or 1,650 sq ft depending on whether the number refers to the space inside your walls or a share of the lobby, staircase and clubhouse. Understanding the three terms is the fastest way to compare two projects honestly.

In short: carpet area is what you can actually use, built-up area adds the walls, and super built-up area adds a share of common spaces. RERA changed the rules so that carpet area must now be disclosed, which is the number that matters most.

Carpet area: the floor you can lay a carpet on

Under RERA, carpet area is defined as the net usable floor area within the internal walls of the apartment, excluding the thickness of the external walls but including internal partition walls. It is the space where you place furniture, walk and live. This is the number that should anchor your decision.

Because RERA made carpet-area disclosure mandatory in the sale agreement, it is now the fairest basis for comparison across projects. Two flats sold on the same super built-up number can have meaningfully different carpet areas.

Built-up area: carpet plus the structure

Built-up area adds the thickness of the walls and, typically, the balcony and utility areas to the carpet area. It is larger than carpet area but still confined to your unit. The difference between carpet and built-up is usually modest, driven mainly by wall thickness and balconies.

Super built-up area: your share of everything common

Super built-up (or saleable) area adds a proportionate share of common spaces such as lobbies, staircases, lift shafts, corridors and sometimes amenity areas. The gap between carpet and super built-up is expressed as the loading factor. A higher loading factor means you are paying for more shared space relative to your private space.

Loading varies by project and by builder philosophy. A generously amenitised tower will often carry a higher loading than a compact, no-frills building. Neither is wrong, but you should know what you are buying.

How to compare two projects fairly

  • Ask for the carpet area in writing, not just the saleable figure.
  • Compute the effective price per sq ft on carpet area, not super built-up, for a true comparison.
  • Ask for the loading factor and compare it across shortlisted projects.
  • Confirm whether balconies and utility spaces are counted, and how.
  • Cross-check the carpet area stated in the brochure against the RERA registration and the sale agreement.
  • Walk the actual flat or a sample unit and sense-check whether the usable space feels consistent with the quoted carpet area.

Why the RERA number is your anchor

Because carpet area is the legally disclosed figure, it is harder to inflate and easier to hold a builder accountable to. When you evaluate value, translate everything back to carpet: a flat that looks cheaper per super-built-up square foot can be more expensive per usable square foot once loading is stripped out.

Treat the loading factor as a lens, not a verdict. Some buyers happily pay for grand common areas; others want every rupee inside their walls. The point is to choose deliberately.

The honest takeaway

There is no single correct area to buy on, but there is a correct area to compare on, and that is carpet. Get it in writing, price everything against it, and you will never be surprised by how small a large-sounding flat feels.

This article is general information, not legal advice. Verify carpet-area figures, loading and pricing against the sale agreement, the RERA registration and current rules for your city, and consult a lawyer or advisor before you commit.