Carpet area, built-up, super built-up: what you actually pay for
The three numbers on every Bengaluru price sheet mean different things, and only one of them is what you actually get to stand in. A worked example, and where to find the real figure.
A Bengaluru price sheet usually leads with one number — "1,450 sq ft, ₹1.15 crore" — and that number is almost never the size of the home you can actually stand in. It is the super built-up area, and it can be a third bigger than the floor space you get.
There are three different areas in play, and a builder is free to advertise in whichever one makes the flat look biggest.
The three areas
Carpet area is the one RERA cares about. Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 defines it precisely: the net usable floor area of an apartment, excluding the area under the external walls, service shafts, an exclusive balcony or verandah, and an exclusive open terrace — but including the area under internal partition walls. In plain terms: the floor you can walk on inside your own four walls, minus balconies, minus the thickness of the outer wall.
Built-up area adds the walls back — the external wall thickness and, usually, the balcony — to the carpet figure. It is roughly what an older sale deed used to quote.
Super built-up area (also called "saleable area") adds a further, proportionate share of everything you don't exclusively own: the lift lobby, the stairwell, the corridor outside your door, sometimes the clubhouse and the gym. This is the number on the hoarding, because it is the biggest of the three, and every other number on the price sheet — the quoted price, the quoted rate per square foot — is calculated against it.
Why RERA carpet area exists
Before the 2016 Act, a builder could quote a flat's size however was most flattering, and two flats named at the same size from two different builders were routinely not the same size at all. RERA's fix was to make carpet area a filed, checkable number and to require the price to be stated per square metre of carpet area in the agreement for sale — Section 4(2)(l)(C) — precisely so a buyer has one number they can compare across builders. What it did not do is stop marketing material from leading with the bigger number. Fourteen years on, super built-up is still what you see first.
The loading, worked through
The gap between super built-up and carpet is called the loading. A flat quoted at 1,450 sq ft super built-up with 35% loading has a carpet area of 1,450 ÷ 1.35 ≈ 1,074 sq ft. The same flat at 55% loading — a taller tower with more shared lobby, more amenity space, a bigger clubhouse — has a carpet area of 1,450 ÷ 1.55 ≈ 935 sq ft. Same quoted size, same hoarding, 139 sq ft of difference in what you can put furniture on.
Run the price the same way. Say both are quoted at ₹8,000 per sq ft on super built-up — ₹1.16 crore either way. On carpet, the first works out to roughly ₹10,800 per sq ft; the second to roughly ₹12,400 per sq ft. You would be paying almost 15% more for the same money, for a smaller home, and nothing on the price sheet would tell you that — because nothing on the price sheet is required to.
| 35% loading | 55% loading | |
|---|---|---|
| Super built-up (quoted) | 1,450 sq ft | 1,450 sq ft |
| Carpet area (what you get) | ≈1,074 sq ft | ≈935 sq ft |
| Quoted price | ₹1.16 cr | ₹1.16 cr |
| Real price per sq ft of carpet | ≈₹10,800 | ≈₹12,400 |
Loading below roughly 18% essentially never happens on a Bengaluru apartment — carpet area, by definition, excludes the walls and the balcony, so even a generously laid-out flat loses more floor than that to structure and shared space. On DOSL's own reading of Bengaluru's filed unit mix, a project reporting a loading outside roughly 1.18×–2.0× (an efficiency of 50–85%) is flagged rather than published as-is, because outside that band the more common explanation is an incomplete filing, not an unusually efficient or wasteful building.
Where to find the real number
The carpet area is not a secret — it is a filed number, on the record, per unit type, in the project's RERA registration. You can look it up directly on K-RERA's project search, or read it on the project's DOSL page, where it is taken from the same filing. Before you sign anything, ask the sales office for the carpet area in writing and do your own division: price ÷ carpet area, not price ÷ super built-up area. It is the only comparison that holds across two different buildings.
This is general information, not financial or legal advice. Confirm the exact carpet area for a specific unit against its RERA filing and the agreement for sale before you transact.