Carpet, Built-up and Super Built-up Area in Bengaluru: What a Buyer Pays For

A Bengaluru buyer named Deepak was thrilled with a 1,300 square foot flat advertised off Kanakapura Road in September 2026, until he measured it. The usable space inside the walls was closer to 800 square feet. He had not been cheated; he had simply paid for super built-up area while living in carpet area. The 500 square foot gap between the two is the single biggest source of confusion, and quiet disappointment, in a Bengaluru apartment purchase.

The short answer. Carpet area is the usable space inside your flat, built-up area adds the walls and balcony, and super built-up area adds your share of common spaces like lobbies and staircases. Builders advertise super built-up, but under RERA the sale must be priced on carpet area, and in Bengaluru today carpet is often only about 60 percent of the super built-up number. The trade-off: a lower loading factor means more usable space per rupee, so the only fair way to compare two projects is on the price per square foot of carpet area, not the glossy super built-up figure.

What do carpet, built-up and super built-up area actually mean?

Carpet area is the net usable floor area inside your flat, the space where you could literally lay a carpet. Under RERA it is defined precisely as the area within the internal walls, excluding the external walls, service shafts and exclusive open balconies, while including the internal partition walls. It is the number that matches how much room you will actually live in.

Built-up area takes the carpet area and adds the thickness of the walls and usually the balcony and utility, so it is larger than carpet but still limited to your unit. Super built-up area, the figure builders advertise, adds your proportionate share of the building's common areas, the lobby, staircases, corridors, lift wells and sometimes amenities. That is why the super built-up number can be dramatically higher than the space you occupy, even though nothing about your flat has changed.

A related term you will hear is saleable area, which builders often use interchangeably with super built-up but which can be even larger, because it may fold in a share of amenities the definition of super built-up does not strictly cover. There is no fixed legal meaning for saleable area, which is exactly why it is risky to rely on. Whenever a brochure quotes a size, the first question to ask is which of these definitions it uses, and the second is what the RERA carpet area is, because only the carpet figure has a precise, legally anchored meaning you can hold the builder to.

What is the loading factor, and why does it matter?

The loading factor is the gap between carpet area and super built-up area, expressed as a percentage added on top of carpet. The formula is simple: super built-up area equals carpet area multiplied by one plus the loading factor. If a flat has 1,000 square feet of carpet and a 30 percent loading factor, the super built-up area is 1,300 square feet, and you are paying for those extra 300 square feet of shared space.

In Bengaluru the loading has crept up over the years. Research reported in 2025 put the city around 41 percent loading, meaning buyers get roughly 60 percent of the paid-for area as carpet, up from about 30 percent loading in 2019. Surveys of recent Bengaluru projects show carpet shares mostly between 60 and 63 percent, ranging from about 56 percent in compact one-bedroom plans to around 72 percent in premium large-format homes. A compact one-bedroom at 56 percent carpet is normal; a three-bedroom at 56 percent deserves hard questions.

Why has loading climbed? Larger lobbies, more amenities, clubhouses, wider corridors and covered parking all count as common area, and their cost is spread across every flat through the loading factor. A project that markets a grand double-height lobby and a resort-style clubhouse is, in effect, asking every buyer to pay for that grandeur in the gap between carpet and super built-up. None of this is hidden, but it is rarely spelt out, so a buyer who only looks at the headline size and price can end up paying a premium for shared glamour rather than private space. Deciding how much amenity you actually value is part of reading the loading factor honestly.

How do the three area measures compare?

The table below lays out what each measure includes and which one the law actually ties your purchase to.

What does RERA require builders to do?

RERA changed the rules decisively in the buyer's favour. Under the central Act, all sales in RERA-registered projects must be based on carpet area rather than super built-up area, and this applies to projects with more than eight apartments or land over 500 square metres, as set out by Karnataka RERA. The builder must state the RERA carpet area in the agreement, which means you can finally compare like with like across projects.

Karnataka RERA goes further on tolerances. Under the state rule on carpet area variation, a builder can charge you extra only if the carpet area increases by up to 3 percent from the agreed figure, and any reduction in carpet area, regardless of the percentage, must be refunded to the buyer. That is a real protection: if your delivered flat is smaller than promised, you are owed money back. To see the wider set of protections a registered project gives you, read our guide on how RERA protects an under-construction buyer.

How should a Bengaluru buyer use these numbers?

Turn the theory into a short routine you run on every shortlisted flat. Work through these steps before you compare prices or sign anything.

1. Ask the builder for the RERA carpet area in writing, not just the super built-up figure.
2. Calculate the loading factor by dividing super built-up by carpet and subtracting one.
3. Re-state the price as rupees per square foot of carpet area for every project you compare.
4. Check that the agreement for sale records the carpet area, since that is the legal basis.
5. Confirm the project is RERA registered and match the carpet area to the RERA disclosure.
6. Ask how the balcony, utility and any exclusive terrace are treated in the numbers.
7. Note the Karnataka rule that a shortfall in carpet area must be refunded to you.

Comparing on carpet area is the single habit that protects you most, because two flats quoted at the same super built-up price can differ sharply in real usable space once the loading is stripped out. A project with a lower loading factor genuinely gives you more home for the same money. It also helps to understand how much a builder is allowed to construct on the land in the first place; our explainer on FSI and FAR in Bengaluru covers that side. If you are evaluating a specific development such as Sobha Arena on Kanakapura Road, ask for its carpet area schedule and loading before you compare it with anything else.

What area tricks should a buyer watch for?

A few patterns recur often enough to name. The first is a price quoted per square foot on super built-up area, which flatters an expensive flat by spreading the cost over inflated square footage; always recompute it on carpet. The second is a brochure that gives a size but never says which definition it uses, leaving you to assume it is bigger than the real carpet. The third is a balcony or terrace counted generously into the size, even though your usable indoor space is smaller than the number suggests.

The fourth, and most consequential, is a mismatch between the size in the brochure and the carpet area in the RERA registration or the agreement for sale. If those two numbers disagree, trust the RERA and agreement figure and ask the builder to explain the gap in writing. A reputable developer will happily give you a clear carpet area, a stated loading factor and a price per carpet square foot. Reluctance to put those three numbers down clearly on paper is itself a useful signal about how the rest of the deal will go.

Frequently asked questions

Is a flat sold on carpet area or super built-up area in Bengaluru?

Under RERA, a flat in a registered project must be sold and priced on carpet area, not super built-up area. Builders may still advertise the super built-up figure, but the agreement and the pricing must be tied to the RERA carpet area. This lets you compare projects fairly on the space you will actually use.

What is a good loading factor in Bengaluru today?

In Bengaluru, carpet is often about 60 to 63 percent of super built-up, which works out to a loading factor of roughly 40 to 45 percent. A compact one-bedroom may sit near 56 percent carpet, which is normal, while a lower loading always means more usable space per rupee. Compare projects on carpet area to judge which offers better value.

Can a builder charge more if the carpet area changes?

In Karnataka a builder can charge extra only if the carpet area increases by up to 3 percent from the figure agreed in your contract. If the delivered carpet area is smaller than promised, by any amount, the builder must refund you for the shortfall. This tolerance rule is a key RERA protection.

How do I compare two flats with different loading factors?

Convert both prices to rupees per square foot of carpet area, not super built-up. Divide the total price by the RERA carpet area for each flat, then compare. Two flats quoted at the same super built-up price can differ sharply once loading is removed, and the one with more carpet area gives you more real home for the same money.

Last updated 2026-09-23. PropNewz Team.