Carpet Area vs Super Built-Up — How to Spot a Bad Deal 2026
A Bengaluru apartment sold as 1,839 sq ft can contain 1,083 sq ft you are allowed to furnish. The gap is called loading, and it varies enough between plans to change which one is a good deal.
Buyer guide | Karnataka RERA definitions | Worked examples | Our Rating: 4.6/5 useful
Our verdict: stop comparing projects on rate per sq ft. Compare them on price per square foot of carpet, and roughly one in five shortlists changes order.
Three numbers, one apartment
Every Bengaluru apartment has at least three areas attached to it, and buyers are routinely quoted the largest one. Carpet area is the net usable floor you can stand on. Built-up area adds the walls and balcony. Super built-up area adds your share of lobbies, staircases, lift cores, the clubhouse and corridors.
The legal definition matters because it is precise. Under the Real Estate (Regulation and Development) Act, carpet area is the net usable floor area of the apartment, excluding external walls, areas under service shafts, exclusive balcony or verandah and exclusive open terrace, but including the internal partition walls. That is the number that must appear in your agreement.
Super built-up area has no statutory definition at all. It is a commercial convention, and the share of common area allocated to your flat is set by the developer. Two projects on the same road can load 30 percent and 42 percent respectively, and both are perfectly legal while meaning very different things for your money.
What a normal loading looks like
| Product type | Carpet efficiency | What drives it |
|---|---|---|
| Older low-rise, pre-2012 | 72 to 80% | Small lobbies, minimal amenity |
| Mid-rise, modest clubhouse | 65 to 72% | Two lifts per core, single clubhouse |
| Current high-rise | 58 to 65% | Large amenity deck, fire refuge floors |
| Premium high-rise | 52 to 60% | Double-height lobby, three-lift cores |
| Indicative bands from Bengaluru projects we have analysed. Always calculate from the actual figures in the agreement. | ||
Low efficiency is not automatically bad. A 58 percent ratio can mean a genuinely large clubhouse, wide corridors and three lifts per core, all of which you use. The problem is that the carpet area figure alone cannot tell you whether you are paying for amenity you will enjoy or for wall thickness and an oversized lobby you will walk through.
What is always bad is variation within one project. If two plans in the same tower, sharing the same clubhouse and the same lift core, return efficiencies of 64.2 percent and 58.9 percent, the difference is not amenity. It is allocation, and the plan carrying the heavier share is subsidising the others.
The only comparison that works
Divide the all-in price by the carpet area. That single calculation strips out every difference in loading convention and gives you a number you can compare across projects, across corridors and across builders. We run it on every project we write up, and it reorders shortlists often enough that we now treat rate per super built-up square foot as marketing rather than data.
| SBUA | Rate | Price | Carpet | Per carpet sq ft | |
|---|---|---|---|---|---|
| Project A | 1,500 | Rs 12,000 | Rs 1.80 Cr | 1,005 (67%) | Rs 17,910 |
| Project B | 1,350 | Rs 12,500 | Rs 1.69 Cr | 972 (72%) | Rs 17,361 |
| Illustrative. Project B looks 4 percent more expensive per sq ft and is actually 3 percent cheaper per sq ft of usable floor. | |||||
Project B is quoted at a higher rate, which is exactly why most buyers eliminate it. Run the calculation and it is the cheaper apartment per square foot of usable floor, and Rs 11.25 lakh less in total. Project A does give 33 more square feet of carpet, but at Rs 11.25 lakh for those 33 feet, you are paying about Rs 34,000 a foot in a project whose going rate is Rs 17,500.
That is the whole technique. You are not trying to find the project with the highest efficiency, because a 72 percent building with a bad location is still a bad buy. You are trying to make sure that when you compare two apartments you believe are equivalent, you are comparing the floor you will live on rather than the floor you will walk across.
A live example of loading gone wrong
We found an unusually clean case at a current Sarjapur Road launch, which publishes carpet area alongside super built-up area for every plan. Two of its three-bedroom plans sit in the same towers, share the same clubhouse and the same lift cores, and differ by 91 square feet of super built-up area.
The 1,748 sq ft plan carries 1,081 sq ft of carpet at Rs 2.40 crore. The 1,839 sq ft plan carries 1,083 sq ft of carpet at Rs 2.50 crore. That is two extra square feet of usable floor for Rs 10 lakh, with efficiency falling from 61.8 percent to 58.9 percent and cost per square foot of carpet rising 8.8 percent.
Nothing improper has happened. The developer published both numbers honestly, and a buyer who does the arithmetic can see it in two minutes. The reason almost nobody sees it is that the price list sorts by super built-up area, which makes the 1,839 look like the bigger apartment. Our full review of that project works through the rest of the plan set.
What you are entitled to see
The carpet area must be stated in the agreement to sell, and it is the figure against which the sale is legally measured. If the final measured area differs beyond the permitted tolerance, the law provides for adjustment, which means the number is not decorative. Ask for it in writing before you pay a booking amount, not after.
You are also entitled to the floor plan with room dimensions. Those dimensions let you sanity-check that figure yourself: add the room areas, allow for internal walls, and the total should land close to the stated figure. A gap of more than 5 percent between your addition and the stated number is worth a direct question.
What you are not entitled to is a breakdown of how the common area was allocated across plans, because no rule requires one. That is precisely why the carpet area number is the only reliable anchor, and why a developer who publishes it voluntarily is giving you something most do not.
Balconies, the other quiet adjustment
An exclusive balcony or verandah is excluded from the statutory figure, which trips up buyers who measure a sample flat and cannot reconcile what they walked through with what the agreement says. A 1,700 sq ft three-bedroom with two balconies can easily carry 90 to 130 sq ft of balcony that counts in the marketed area and not in the legal one.
That is not a trick, and balcony space is genuinely valuable in Bengaluru, where a covered balcony is usable almost every day of the year. But it is a different kind of floor from a bedroom, and it should be valued differently. We tell buyers to treat balcony at roughly half the rate of enclosed floor when comparing two plans.
The practical step is to ask for the balcony area as a separate line. Once you have it, you can build a comparison that holds: enclosed usable floor, plus balcony at half weight, against all-in price. Two plans that looked identical on the marketed number often separate by 4 to 6 percent once balconies are weighted this way.
Five questions to ask at every site visit
First, what is the carpet area of this specific plan, in writing. Second, what is the carpet area of every other plan in the same tower, so you can compare efficiencies within one building. Third, is the balcony included in the quoted area and if so how is it counted.
Fourth, does the quoted price include floor rise, preferential location charges, club membership and advance maintenance, because a comparison of carpet rates is meaningless if one project quotes gross and the other quotes net. Fifth, what tolerance does the agreement allow between the stated and the finally measured area.
Those five answers take ten minutes to collect and will tell you more about value than an hour in the sample flat. Our companion guide on how to read a builder price list covers the charges that sit outside the headline rate and distort these comparisons.
What to do with the number
Build a three-column sheet for your shortlist: all-in price, carpet area, and price divided by carpet. Put every project you are considering in it, including the ones you have already mentally rejected on headline rate. In our experience about one shortlist in five changes order once that column exists.
Then apply judgement rather than arithmetic. A project that is 4 percent more expensive per square foot of carpet but sits 6 km closer to your office is still the better buy. The calculation does not make the decision for you; it just stops you making it on a number the developer chose.
For a worked application across a whole corridor, see our analysis of the Mullur project where we first ran these figures, and our note on how the maths changes above Rs 3 crore, where loading tends to be heaviest.
Frequently asked questions
What exactly is carpet area?
The net usable floor area of the apartment, excluding external walls, service shafts, exclusive balcony or verandah and exclusive open terrace, but including internal partition walls. It must be stated in your agreement to sell.
What is a good efficiency ratio in Bengaluru?
Current high-rise projects run 58 to 65 percent, mid-rise 65 to 72, and premium towers with large lobbies can fall to 52. Anything below about 58 percent deserves a question about what the extra loading buys you.
Is super built-up area illegal?
No. It has no statutory definition, which is different from being banned. Developers may market on it, but the agreement must state carpet area, and that is the figure the sale is legally measured against.
How do I calculate price per square foot of carpet?
Divide the all-in price by the carpet area in square feet. Use the all-in figure including charges and taxes, and use the same basis for every project, or the comparison breaks down immediately.
What if two plans in one tower have different efficiencies?
Then the difference is allocation, not amenity, since both share the same lobbies and clubhouse. The plan with the lower efficiency is carrying a heavier share of the common area, and you should price that into your offer.
