The price list says 1,450 square feet. The floor your family can actually walk on is closer to 1,100. Both numbers are real. Only one of them is defined in law, and it is not the big one.
This guide explains what each number contains. It also shows how to work out the gap between them, and where to read the figure your builder has already filed with the state.
Key Takeaways
- Carpet area is the only one of the three defined in law, in Section 2(k) of the RERA Act, 2016.
- Built-up adds your walls. Super built-up adds your share of lobbies, stairs, the lift and the club house.
- The gap between carpet and super built-up is called the loading factor. No law sets a limit on it.
- Two quotes can only be compared once both are converted to a rate on carpet area.
- Your builder declared the carpet area to GujRERA before selling, so you can read it there yourself.
Which of These Three Numbers Is Fixed by Law?
Only carpet area. The RERA Act, 2016 calls it "the net usable floor area of an apartment" (RERA Act, 2016). The Act then lists what comes out of that figure. External walls go. So do service shafts, your exclusive balcony or verandah, and any exclusive open terrace.
Read that list slowly, because two of them surprise people. Your outer walls sit outside the number, and so does your balcony. What the Act does count is the area covered by the internal walls between your own rooms.
That is the number worth arguing about, because it is the one you live on. For a family moving up from a 2 BHK, it is also the number that decides whether the new place feels bigger.
This matters more in north Ahmedabad than people expect. A buyer looking at Zundal, Chharodi and Adalaj in the same month will see towers of very different shapes. A slim building on a small plot and a large scheme with a club house do not share out common area in the same way. The brochures will still describe both in square feet, and the word next to that number is the one to read.
What Do Built-Up and Super Built-Up Add?
Built-up area takes the carpet area and adds the walls, and usually the balcony. Super built-up goes further. It adds your share of what the building holds in common: the lobby, the stairs, the lift, the club house.
Neither term appears in the Act. That is the part most buyers miss. Because no law defines them, two builders can calculate them in two different ways, and both can be telling the truth about their own arithmetic.
So one builder's 1,450 square foot flat and another's may hold quite different amounts of living space. The only way to know is to ask both for the carpet area.
What Is the Loading Factor?
It is the gap between what you pay for and what you can walk on, written as a percentage. The sum is simple. Take the super built-up area, subtract the carpet area, then divide by the carpet area.
Use the flat in the diagram. Super built-up is 1,450 and carpet is 1,100, so the gap is 350 square feet. Divide 350 by 1,100 and you get 32%.
In the plans we have read around Ahmedabad, loading usually sits between a quarter and a third. A higher figure is not automatically a cheat. A building with a wide lobby, a club house and two lifts has more common area to share out. You may well want those things.
What pushes the number up is easy to spot on a plan. Wide corridors, two lifts for a small tower, a big entrance lobby and a large club house all add common area. A simple building with one lift and a narrow landing carries less. What matters is that you know the number before you sign, and that nobody sets it after you have paid.
How Do You Compare Two Builders' Quotes?
Convert both to a rate on carpet area, then compare. Until you do that, you are comparing two numbers that were built differently.
Here is the same money against two different loadings.
| What the builder quotes | Builder A | Builder B |
|---|---|---|
| Super built-up area | 1,450 sq ft | 1,450 sq ft |
| Rate quoted | ₹5,000 per sq ft | ₹5,000 per sq ft |
| Total price | ₹72,50,000 | ₹72,50,000 |
| Loading factor | 25% | 38% |
| Carpet area you get | 1,160 sq ft | 1,051 sq ft |
| Real rate on carpet | ₹6,250 per sq ft | ₹6,898 per sq ft |
Same headline price. Same headline size. One flat gives your family 109 more square feet of floor. The figures above are an illustration, and the sum is exactly the one to run on two real quotes.
Ask for the loading in writing while you are at it. A builder who knows the figure will say it without checking. A builder who has to call somebody has told you something too.
This is also worth doing before you compare across areas. A quote in Zundal and a quote in Chharodi can only be judged side by side once both are on a carpet basis.
Where Is the Carpet Area Written Down?
In three places, and you can reach two of them without asking anyone.
On the GujRERA portal. Before a project can be sold, the promoter files an application with the authority. It must state "the number, type and the carpet area of apartments for sale in the project". Balcony, verandah and open terrace areas are declared separately. That filing sits on the GujRERA website under the project's registration number. Our guide on how to check a RERA registration walks through finding it.
In the sanctioned plan. The Act gives you a right to it. An allottee "shall be entitled to obtain the information relating to sanctioned plans, layout plans along with the specifications, approved by the competent authority". The promoter is also required to make those plans available at the time of booking.
In your agreement. The carpet area belongs in the agreement for sale, in figures, next to the price and the unit number. Check that this figure matches the GujRERA filing and your price sheet. Three documents, one number. If it is missing from the agreement, stop and ask, because the agreement is the paper a court would read.
What If the Figure Turns Out to Be Wrong?
The Act has something to say about that. Say you paid an advance on the strength of a notice, an advertisement or a prospectus. If you then suffer loss "by reason of any incorrect, false statement included therein", the promoter has to compensate you. The same applies to a model apartment you were shown.
That is why the number should reach you in writing. A printed price sheet, an email or the agreement itself all count as something you relied on. A figure quoted across a table on a Sunday site visit leaves no trace at all.
Keep the brochure you were given. Keep the price sheet. If the final measured carpet area differs from what you were sold, those papers are the difference between a complaint and an argument.
What Should You Ask Before You Book?
Five questions, and all five deserve answers on paper.
- What is the carpet area of this flat, as defined under RERA?
- What is the super built-up area, and what does your loading include?
- Does the quoted rate apply to carpet or to super built-up?
- Which GujRERA registration number covers this tower?
- Is the carpet area written into the agreement for sale?
These sit alongside the wider set in our guide to questions to ask a builder before buying a flat. Take the list with you on the Sunday morning site visit and write the answers on it. A sales office is a friendly place, and the numbers blur by the third flat. A builder who answers all five without pausing has answered the questions that change what you get. At Swarnim Skyline and our other ongoing projects, the sizes for each unit are published. Ask our team for the carpet figure in writing and you will get it.
The Short Version
Carpet area is the floor you live on, and it is the only one of the three numbers that the law defines. Built-up and super built-up are useful for a builder and less useful for you.
Before you compare two flats, convert both prices to a rate on carpet. Before you book either one, read the carpet area on the GujRERA filing and check it against the price sheet in your hand.
If the two do not match, you have learned something important about the builder, and you have learned it while it still costs you nothing.
Frequently Asked Questions
Both are used in the market. The law defines carpet area and makes the promoter declare it. It does not stop a builder from quoting a rate on super built-up. What matters is that you know which basis the rate uses before you compare it with anything else.
There is no legal answer, because no rule sets one. In the plans we see around the city, a quarter to a third is common. If a builder quotes 40% or more, that is not a reason to walk away on its own. It is a reason to ask what the extra space buys you, and to put the same question at the next project you visit. Ask what the loading includes. A tower with two lifts, a club house and wide lobbies will carry more common area than a plain six-storey building.
No. The Act specifically excludes the exclusive balcony or verandah area, and the exclusive open terrace area, from carpet area. Those are measured separately, and the promoter has to declare them separately as well.
On the value of the transaction. A floor measurement does not set it. Our guide to stamp duty and registration charges in Gujarat sets out how the figure is worked out and what the current rates are.
No, and it is worth correcting politely. Built-up is your flat plus its walls. Super built-up adds a share of the building's common areas on top. If someone uses the words interchangeably, ask for all three figures in writing and the confusion usually resolves itself.