Carpet area, built-up, super built-up: what you are actually buying

A flat advertised at 1,150 sq ft might give you 700 sq ft of floor. Both numbers can appear in the same brochure, neither is a lie, and the difference is the single most common reason buyers feel misled after they move in.

Three terms are in circulation. Only one of them is floor you can put furniture on.

Carpet area

The usable floor inside your walls. Under the Real Estate (Regulation and Development) Act, 2016, carpet area is the net usable floor area, excluding the external walls, service shafts, the balcony and any open terrace — but including the internal partition walls of the flat.

This is the number that matters. It is what you sweep. It is also the number RERA requires a developer to disclose and to sell on, precisely because the other two were being used to make flats sound larger than they are.

Built-up area

Carpet area plus the walls themselves, plus the balcony. Typically 10–20% more than carpet area.

Nothing here is dishonest — walls are real and a balcony is useful. But you cannot put a bed in a wall.

Super built-up area

Built-up area plus your share of everything the building holds in common: the lobby, staircases, lift shafts, corridors, sometimes the clubhouse, the gym, the society office. This is often called the "loading".

Loading is not standardised. A building with a 25% loading gives you substantially more flat for the same headline number than one at 40%. Two projects on the same road can quote the same super built-up figure and hand you flats that differ by a couple of hundred square feet of actual floor.

Doing the arithmetic

If a flat is quoted at 1,150 sq ft super built-up with a 35% loading:

carpet area ≈ 1,150 ÷ 1.35 ≈ 852 sq ft

And the price per square foot moves with it. A flat at ₹1.15 crore is:

• ₹10,000 per sq ft on super built-up
• ₹13,500 per sq ft on carpet

The second number is the one to compare between projects, because the first one depends on a loading percentage each developer chooses for themselves.

What to ask for, in writing

1. The carpet area, stated as carpet area. It is on the RERA registration and in the agreement for sale. Ask for both.
2. The loading percentage. If nobody will put a number on it, calculate it: (super built-up ÷ carpet) − 1.
3. Whether the balcony is included in the figure you were quoted, and at what proportion.
4. The price per square foot on carpet, so you are comparing like with like.

Measure it yourself

You are allowed to. Take a laser measure to the site visit — they cost a few hundred rupees — and measure the rooms. Add them up. Compare with the carpet area on paper.

Most of the time it matches. When it does not, you want to know before you sign, not after. A discrepancy is also something you can raise with the developer and, if it is material and the project is registered, with the state RERA authority.

Any developer who is uncomfortable with you measuring the flat you are about to buy has told you something useful.

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We measure the carpet area of every property we film, and publish the number next to the one on the brochure. If they differ, the page says so.