Carpet area vs built-up area vs super built-up area, explained

What is carpet area under RERA?

Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 defines carpet area as the net usable floor area of an apartment, excluding the area covered by the external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but including the area covered by the internal partition walls of the apartment.

In plain words: measure every room wall to wall, add the thickness of internal walls, and leave out the outer walls, shafts, balconies and terraces. Builders show exclusive balconies and terraces separately in the agreement for sale.

What are built-up and super built-up area?

Built-up area is not defined in the RERA Act; it is market usage. It normally means carpet area plus the external walls, and often the balcony or terrace too. Super built-up area (also called saleable area) adds a proportionate share of common areas — staircases, lift lobbies, corridors, and sometimes the clubhouse or pool.

Because neither term has a statutory formula, two builders can calculate them differently. That is why the RERA Act requires builders to disclose carpet area for registered projects (Section 4(2)(h)), and why state rules’ model agreements for sale — Haryana’s 2017 rules, for example — price the unit on carpet area.

What is the loading factor?

The Loading factor is the ratio of super built-up area to carpet area. A loading of 1.30 means the quoted size is 30 % larger than the space you can actually use. Loading is often expressed as a percentage — the same 1.30 is “30 % loading”.

There is no legal cap on loading. It depends on how much common space a project has and how the builder distributes it. A tower with a large clubhouse will usually carry more loading than a simple four-storey building.

A worked example: one 2 BHK, three numbers

Here is an illustrative 2 BHK flat in Pune. The figures are made up to show the arithmetic, not market data.

• Quoted at ₹9,000 per sq ft of super built-up area, the flat costs ₹88.2 L.
• The same ₹88.2 L over 700 sq ft of carpet works out to ₹12,600 per sq ft of carpet.
• A second flat quoted at ₹11,500 per sq ft of carpet would be cheaper per usable sq ft, even though its headline rate looks higher.

How do you convert between the three?

If you know the loading factor, carpet area ≈ super built-up area ÷ loading factor, and super built-up ≈ carpet × loading factor. Without the builder’s breakdown, any conversion is an estimate. The free carpet area calculator in our tools section runs the arithmetic both ways, and the area converter handles sq ft, sq m and gaj.

What should buyers check?

Before you pay a token amount, ask for these in writing:

• The RERA registration number of the project, and the carpet area of your unit type on the state RERA portal.
• The carpet area stated in the agreement for sale, with the balcony and terrace areas listed separately.
• The price per sq ft of carpet area, and every other charge on the Cost sheet (PLC, Floor rise, parking).
• For resale flats, the area in the original agreement or sale deed — older documents often quote built-up or super built-up area only.
• A tape measurement of the rooms at the site visit if the numbers look tight.

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