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Carpet Area Calculator — What the Loading Factor Actually Costs You
A flat advertised at ₹6,000 a square foot on super built-up area, with 30% loading, is ₹7,800 a square foot of floor you can actually stand on. The price never changed — only the number it was divided by. Convert your own figures and see all three rates at once.
Carpet · built-up · super built-up
Enter whichever area figure you have — the other two are worked out from it. Carpet area is defined by statute at Section 2(k) of RERA; built-up and super built-up are not defined anywhere in the Act, which is why they vary by builder.
Educational calculators — always consult a licensed professional before making financial decisions.
Whichever one you were given. The other two are worked out from it — you do not need all three.
The big number in the brochure.
The area figure as printed, on the basis you just picked.
Super built-up is carpet area plus this much. It is in your builder's own literature.
Mostly wall thickness plus the exclusive balcony.
The comparison below only works once there is a rupee figure attached to the area.
The usual brochure format.
The headline rate, before floor rise, parking, club charges and taxes.
This is the question the whole page turns on. If the brochure does not say, ask.
The big number in the brochure.
What you actually pay, per square foot of carpet area
₹7,800 / sq ft
You were quoted ₹6,000 / sq ft on super built-up area
The same ₹72 L, priced three ways
Not a single rupee changes between these rows. Only the area the price is divided by changes — which is why a per-square-foot rate means nothing until you know its basis.
| Definition | Area | Effective ₹ / sq ft |
|---|---|---|
| Carpet areaDefined by statute — RERA s.2(k) | 923.08 sq ft85.76 sq m | ₹7,800 |
| Built-up areaMarket convention, not defined in RERA | 1,015.38 sq ft94.33 sq m | ₹7,091 |
| Super built-up areaMarket convention, not defined in RERA · the basis you were quoted on | 1,200 sq ft111.48 sq m | ₹6,000 |
You were quoted ₹6,000 per sq ft on super built-up area. Measured against the floor you can actually stand on, the rate is ₹7,800 per sq ft — 30.0% higher. That is not a mark-up the builder is hiding; it is the arithmetic of the loading factor you entered, made visible.
What the loading is costing you
Area you pay for
1,200 sq ft
Area you can stand on
923.08 sq ft
The difference
276.92 sq ft · ₹16.62 L
That 276.92 sq ft is not wasted — it is the lobby, the lift, the staircase and the clubhouse, and you get the use of all of them. The point is that it is ₹16.62 L of your purchase, and it is only visible once someone divides the price by the right number. What no Indian authority regulates is how much of the common area a builder may load, or what may be counted in it.
Based on
Section 2(k) — the statutory definition
“carpet area” means the net usable floor area of an apartment, excluding the area covered by the external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but includes the area covered by the internal partition walls of the apartment.
The Real Estate (Regulation and Development) Act, 2016. Quoted from Haryana Real Estate Regulatory Authority, Gurugram (Sale of Apartments/Floors in a Real Estate Project on the basis of Carpet Area) Regulations, 2021 — Haryana Government Gazette No. 20–2021, Part III, 18 May 2021, reproducing section 2(k) of the Act, checked 2026-09-02. Built-up area and super built-up area have no definition in the Act at all, which is why they vary between builders — the regulator's own words are that the practice of selling on super area is “illegal, misleading, ambiguous, opaque” (HRERA Gurugram (Sale of Apartments/Floors on the basis of Carpet Area) Regulations, 2021, paragraph 1(ii) — Haryana Government Gazette No. 20–2021, 18 May 2021).
Definitional arithmetic, not a valuation. The loading factor and wall allowance are the figures you entered — neither is published by any Indian authority, because neither is regulated, so both must come from your builder's own area statement or agreement for sale. This page quotes no price and no market rate. Floor-rise charges, preferential location charges, parking, club and maintenance deposits, GST, stamp duty and registration all sit outside the figures above.
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Only one of these three numbers is defined by law
This is the fact that makes the comparison worth doing. Carpet area is defined in Section 2(k) of The Real Estate (Regulation and Development) Act, 2016:
“carpet area” means the net usable floor area of an apartment, excluding the area covered by the external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but includes the area covered by the internal partition walls of the apartment.
Built-up area and super built-up area appear nowhere in the Act. There is no statutory rule about what may be counted in a super built-up figure, or how much of the common area a builder may load onto your flat. That absence is not an oversight in the Act — it is the reason the Act mandates carpet area in the first place.
Regulators have said so in blunt terms. Notifying its carpet-area regulations, the Haryana Real Estate Regulatory Authority recorded that the practice of selling on super area is “illegal, misleading, ambiguous, opaque, and gives rise to confusion and complexities”, and treats an agreement drawn on any other basis as an unfair practice. Marketing material still quotes it, because it produces the smallest-looking number per square foot.
The same ₹6,000 a square foot, at seven different loading factors
A 1,200 sq ft flat quoted at ₹6,000 a square foot on super built-up area costs ₹72 L whatever the loading factor is. What the loading changes is how much flat you get for it. The rate is a round illustration figure, not a quote and not a market rate — put your own numbers into the calculator above.
| Loading | Carpet area | Real ₹ / sq ft | Common area you pay for |
|---|---|---|---|
| 15% | 1,043 sq ft | ₹6,900 | 157 sq ft · ₹9.39 L |
| 20% | 1,000 sq ft | ₹7,200 | 200 sq ft · ₹12 L |
| 25% | 960 sq ft | ₹7,500 | 240 sq ft · ₹14.4 L |
| 30% | 923 sq ft | ₹7,800 | 277 sq ft · ₹16.62 L |
| 35% | 889 sq ft | ₹8,100 | 311 sq ft · ₹18.67 L |
| 40% | 857 sq ft | ₹8,400 | 343 sq ft · ₹20.57 L |
| 45% | 828 sq ft | ₹8,700 | 372 sq ft · ₹22.34 L |
Read the first and last rows together. At 15% loading the buyer gets 1,043 sq ft of usable floor; at 45% they get 828 sq ft — nearly 216 sq ft less — for identical money. Two projects advertising the identical rate can differ by that much, and nothing on either brochure will tell you.
How to get your own loading factor
Do not take ours. The default in the calculator is a common metro figure offered so the page does something on first load, and no Indian authority — not the RBI, not the NHB, not any state RERA — publishes a loading factor, because loading is not regulated.
You have two reliable routes. The first: your agreement for sale must state the carpet area. Divide the super built-up figure in the brochure by it, subtract one, and that is your loading factor exactly. The second: ask the builder for the area statement in writing, itemising what is loaded into the super built-up figure. A seller who will not put it in writing has told you something useful.
One convention worth stating, because Indian usage is not consistent about it: this calculator treats loading as a percentage of carpet area, so 30% loading means super built-up = carpet × 1.30. That is how brochures overwhelmingly use the term. If your builder defines it against built-up area instead, the arithmetic still works — enter their two area figures directly and read the derived loading off the result.
Where this fits in the purchase
Once you have the carpet figure, the rest of the cost of the flat is calculable. Stamp duty and registration are charged on the agreement value, not the area, and they vary by state and in several states by the gender of the buyer — the stamp duty calculator and the property registration cost calculator model both. On an under-construction flat there is GST on top. And to work out what the flat costs you monthly rather than once, the home loan EMI calculator takes the total from here straight through to an instalment.
If you are building rather than buying, the area basis matters just as much: a construction quote per square foot is almost always against built-up area, which the house construction cost calculator assumes.
Sources
- The Real Estate (Regulation and Development) Act, 2016, Section 2(k) — quoted verbatim from Haryana Real Estate Regulatory Authority, Gurugram (Sale of Apartments/Floors in a Real Estate Project on the basis of Carpet Area) Regulations, 2021 — Haryana Government Gazette No. 20–2021, Part III, 18 May 2021, reproducing section 2(k) of the Act. Checked 2026-09-02.
- HRERA Gurugram (Sale of Apartments/Floors on the basis of Carpet Area) Regulations, 2021, paragraph 1(ii) — Haryana Government Gazette No. 20–2021, 18 May 2021 — the regulator's recital on super-area selling. Checked 2026-09-02.
- Haryana Real Estate Regulatory Authority, Gurugram
- Ministry of Housing and Urban Affairs — the Act and its rules
No price, market rate or loading factor is asserted on this page. The conversion is definitional arithmetic and every figure that drives it is your own input, which is why nothing here can go stale into a wrong number.
About this calculator
What is carpet area, and how is it defined under RERA?+
Section 2(k) of The Real Estate (Regulation and Development) Act, 2016 defines it in terms: “carpet area” means the net usable floor area of an apartment, excluding the area covered by the external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but includes the area covered by the internal partition walls of the apartment. In plain words, it is the floor you can stand on — bedrooms, living and dining rooms, kitchen, bathrooms, storage and any staircase inside the flat, plus the internal walls between them. It excludes the external walls, the service shafts, and your exclusive balcony, verandah or open terrace. It is the only one of the three Indian area figures that has a statutory definition, and it is the basis on which an apartment must be sold. Source: Haryana Real Estate Regulatory Authority, Gurugram (Sale of Apartments/Floors in a Real Estate Project on the basis of Carpet Area) Regulations, 2021 — Haryana Government Gazette No. 20–2021, Part III, 18 May 2021, reproducing section 2(k) of the Act, checked 2026-09-02.
How do I convert super built-up area to carpet area?+
Divide by one plus the loading factor. On the dominant Indian convention, super built-up area = carpet area × (1 + loading), so a 1,200 sq ft flat quoted at 30% loading has a carpet area of 1,200 ÷ 1.30 = 923.08 sq ft. Built-up area sits between the two at carpet × (1 + wall allowance); at a 10% allowance that is 1,015.38 sq ft. The loading factor is not something you can look up — it is not regulated and no Indian authority publishes it, so it has to come from your builder's own area statement. Ask for it in writing, because the difference between 20% and 45% loading on the same flat is the difference between paying for 1,200 sq ft and paying for roughly 1,450.
Why is the price per square foot different on carpet area?+
Because the price of the flat does not change — only the number you divide it by does. A 1,200 sq ft super built-up flat advertised at ₹6,000 per square foot costs ₹72,00,000 in total. That same ₹72,00,000 spread over its 923.08 sq ft of carpet area is ₹7,800 per square foot, and over its 1,015.38 sq ft of built-up area is ₹7,091. A 30% loading factor raises the real price per usable square foot by exactly 30%, which is why two projects cannot be compared on their headline rates unless both quote the same basis. Read the other way, a flat genuinely worth ₹32,000 a square foot on carpet can be advertised at ₹22,069 a square foot at a 45% loading, without a single rupee changing hands differently.
What is the difference between built-up area and super built-up area?+
Built-up area is your carpet area plus the footprint of the external walls and, in most usage, the exclusive balcony and terrace — a wall-thickness allowance, commonly around 10%. Super built-up area adds your apportioned share of the common areas on top of that: lobbies, staircases, lifts, corridors, the clubhouse, sometimes the generator and pump rooms. The critical point is that neither term is defined anywhere in the Real Estate (Regulation and Development) Act, 2016. Only carpet area is. That is precisely why the two vary between builders and between projects — there is no rule saying what may be loaded into a super built-up figure or how much of it.
Is it legal for a builder in India to sell a flat on super built-up area?+
The Act requires apartments to be sold on the basis of carpet area, and regulators have said so in blunt terms. The Haryana Real Estate Regulatory Authority, notifying its carpet-area regulations, recorded that "The definition of super area as provided in various builder-buyer agreements is vague and there are wide variations in the definition. … The practice of sale of real estate on super area basis is illegal, misleading, ambiguous, opaque, and gives rise to confusion and complexities and at times result into avoidable litigation." and treats an agreement for sale drawn on any other basis — super area, covered area, saleable area or any other local nomenclature — as an unfair or fraudulent practice. Marketing material still routinely quotes super built-up because it produces the lowest-looking rate per square foot. Your defence is arithmetic: get the loading factor in writing, convert the quoted rate back to carpet, and compare projects on that number. Source: HRERA Gurugram (Sale of Apartments/Floors on the basis of Carpet Area) Regulations, 2021, paragraph 1(ii) — Haryana Government Gazette No. 20–2021, 18 May 2021, checked 2026-09-02.
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Cost ranges and rates here are checked against contractor quotes and published industry data. If a number still looks off, email Support@RealCostIQ.com and we'll review and fix it.