Meghna compared two Bengaluru flats that both called themselves 1,200 square feet, at almost the same price, and assumed they were the same size. They were not. When she asked for the carpet area, the RERA number for the actual usable space inside each flat, one came back at around 850 square feet and the other at around 780. The same headline figure hid a difference of seventy square feet of real living space, a whole small room, simply because the two builders loaded their common areas differently. The number on the brochure had told her almost nothing. The carpet area told her everything.

The short answer. Carpet area is the net usable space inside your flat, and under RERA it is the basis on which flats must be sold, not the inflated super built up figure that builders once quoted. The trade off to understand is between the headline size and the real one. A large super built up number can make a flat sound spacious, but the carpet area is the space you actually live in, so it is the only figure worth comparing across projects.

What does carpet area mean under RERA?

Carpet area is the net usable floor area inside your flat, defined precisely by RERA. The law describes it as the net usable floor area of an apartment, excluding the area covered by the external walls, the areas under service shafts, and the exclusive balcony or verandah area and exclusive open terrace area, while including the area covered by the internal partition walls. Strip away the legal language and it means the space you could actually spread a carpet across, the floor you live on. This precise definition was one of the most important reforms RERA brought, because before it, builders used vaguer and larger measures that made flats sound bigger than the space you could use. You can read the framework on the Karnataka RERA portal. When a builder quotes you a carpet area, they are quoting the number that the law has pinned down, and that is exactly why it is trustworthy.

The value of a fixed definition is comparability. Because carpet area means the same thing everywhere, two flats measured this way can be compared directly, which is something the old figures never allowed.

How do carpet, built up and super built up differ?

They are three measures of the same flat, each larger than the last. Carpet area is the usable space inside. Built up area takes that carpet area and adds the thickness of the walls and the balcony, so it is a little larger. Super built up area goes further still, adding your proportionate share of the common areas of the building, the lobbies, staircases, lifts, corridors and amenities like the clubhouse. Because it piles on the shared spaces, super built up is always the largest of the three, and carpet area always the smallest. The gap between them is where buyers used to get lost. A flat sold on super built up could look generous on paper while offering far less usable room than the number suggested. The table below lines up the three measures.

Read the three area rows from top to bottom and you are watching the number grow while the space you actually live in stays the same. That is the whole trick the old super built up basis played, and it is the trick RERA was designed to end.

What is the loading factor, and why watch it?

Loading is the gap between the super built up area and the carpet area, and it decides how much of what you pay for is actually inside your flat. It is usually expressed as a percentage of the carpet area. If a flat has a carpet area of 800 square feet and a super built up area of 1,200, the loading is the extra 400 square feet added on, a loading of fifty percent. Two projects with the same super built up size can have very different carpet areas, precisely because their loading differs. A higher loading means more of the headline size is common area rather than your own floor, so you get less usable room for the same money. This is why comparing carpet areas, rather than super built up figures, is the single most useful habit a Bengaluru buyer can adopt. It strips away the loading and compares like with like. Our guide on the undivided share of land covers a related area concept that also affects what you truly own.

None of this makes common areas bad. Lobbies, lifts and a clubhouse are real value, and you do share in them. The point is simply to see the loading for what it is, so you are choosing it consciously rather than paying for it without noticing.

Why does RERA insist on the carpet area basis?

Because it protects buyers from paying for space they cannot use. Before RERA, a buyer could be charged on a super built up figure that no rule pinned down, and different builders inflated it to different degrees, making honest comparison almost impossible. RERA changed this by requiring that an apartment be quoted and sold on its carpet area, the defined usable space. This is not a minor formatting rule, it is a core buyer protection, because it ties your price to something real and consistent. In a RERA registered Bengaluru project, the carpet area is therefore the number that should anchor your decision. If a sales conversation keeps steering you back to the super built up figure, gently steer it back to carpet, because that is the measure the law and your own comfort both care about. Our explainer on allottee rights and duties under RERA sets out the wider protections you can rely on.

Where do you find the carpet area you can trust?

Look for the carpet area in the documents that carry legal weight, not just the glossy brochure. The most reliable place is your agreement to sell or sale agreement, where the carpet area of your specific flat should be stated clearly, because that is the figure the builder is bound to. The project listing on the state RERA portal is another dependable source, since a registered project has to declare its details there. A brochure or a sales presentation can quote whatever it likes, so treat those as a starting point and always confirm the number against the agreement and the RERA record. If the carpet area in your agreement is smaller than what the sales team led you to expect, that mismatch is exactly the kind of thing to raise before you sign, not after. A responsible builder will state the carpet area plainly and consistently across every document, and any reluctance to put a clear carpet figure in writing is itself a signal worth heeding. The rule of thumb is simple. The number that matters is the one written into the document you actually sign, expressed as carpet area, and everything else is marketing until it is confirmed there.

How should a buyer use these numbers?

Anchor every comparison on carpet area, and treat super built up as background. The mistake Meghna nearly made was comparing headline sizes. You can avoid it by making the carpet area the first number you ask for. Work through the checklist below in order.

1. Ask for the RERA carpet area of the exact flat, in writing, not just the super built up size.
2. Note the super built up figure too, so you can calculate the loading.
3. Work out the loading as the gap between super built up and carpet area.
4. Compare flats across projects on carpet area, never on super built up.
5. Divide the price by the carpet area to get a true price per usable square foot.
6. Check the carpet area in your agreement matches what the sales team quoted.
7. Walk the actual flat or a sample unit to feel whether the carpet area matches your needs.

Following this order turns square footage from a marketing weapon into a fair comparison. For a project such as Brigade Citrine, asking for the carpet area and the loading up front lets you judge how much real living space your money buys, rather than being swayed by a super built up figure that every builder can inflate in their own way. The home you live in is the carpet area. Buy that number, not the brochure one, and you will never again mistake a bigger headline for a bigger home.

Common questions from Bengaluru buyers

What is carpet area under RERA?

Carpet area is the net usable floor area inside your flat. Under RERA it excludes the area covered by external walls, service shafts, the exclusive balcony or verandah and the exclusive open terrace, while including the internal partition walls. It is the space you can lay a carpet on, and the basis on which flats must be sold.

What is the difference between carpet, built up and super built up area?

Carpet area is the usable space inside your flat. Built up area adds the thickness of the walls and the balcony to that. Super built up area goes further and adds your proportionate share of common areas like lobbies, staircases, lifts and the clubhouse. So super built up is always the largest figure and carpet area the smallest.

Does RERA require flats to be sold on carpet area?

Yes. Under RERA a builder must quote and sell an apartment on the basis of its carpet area, not the older super built up figure. This was a deliberate reform to stop buyers being charged for an inflated area. So in any RERA registered Bengaluru project, the carpet area is the number that should anchor your price comparison.

What is loading, and why does it matter?

Loading is the gap between the super built up area and the carpet area. A higher loading means a bigger share of common areas is added on, so you get less usable space for the same headline size. Comparing carpet area across projects, rather than super built up, cuts through different loading factors.

Last updated 2026-08-08. PropNewz Team.