Area & Measurement
What is Carpet Area?
The single number that tells you how much flat you are actually buying — and the one builders spent decades not showing you.
The short answer
Carpet area is the net usable floor space inside your apartment — the area you could literally lay a carpet over. It excludes the thickness of external walls, service shafts, balconies and open terraces, but it includes the internal partition walls between your rooms.
Since RERA came into force in May 2017, builders in India must state carpet area in the agreement. It is typically around 30% smaller than the super built-up area they advertise — which means the real price per square foot is roughly 30% higher than the number on the brochure.
What is carpet area?
Carpet area is the floor space you can actually use. Stand inside the flat, look at the ground, and every square foot you can walk on, furnish or lay a carpet across is carpet area. Everything else — the walls holding the building up, the lift lobby outside your door, the shaft carrying the plumbing — is not.
It sounds obvious. It has not historically been how flats were sold. For years, Indian developers quoted super built-up area, a figure that bundles your flat together with a share of the lobbies, staircases, lifts and clubhouse. A buyer paying for 1,200 sq ft would take possession and find a home that felt closer to 850. Nothing illegal had happened. The number was simply measuring something other than the thing they wanted to know.
The Real Estate (Regulation and Development) Act, 2016 — RERA — ended that. It defined carpet area in law and made disclosing it mandatory.
The RERA definition
Section 2(k) of the RERA Act defines carpet area as 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
- exclusive open terrace area
— but including the area covered by the internal partition walls of the apartment.
RERA carpet area includes internal walls. The traditional, literal meaning of carpet area — the area you could carpet — excludes every wall, because you cannot lay a carpet on a wall. These are two genuinely different numbers, and RERA's is the larger of the two, usually by 3–5%.
So when a builder says “RERA carpet area: 850 sq ft”, the space you can actually furnish is a little under 850. Not a scandal, but worth knowing before you plan the furniture.
What's in, what's out
| Space | In RERA carpet area? | Why |
|---|---|---|
| Bedrooms, living, dining | Included | Net usable floor space — the core of the definition |
| Kitchen | Included | Usable floor space inside the apartment |
| Bathrooms & toilets | Included | Usable floor space inside the apartment |
| Internal partition walls | Included | Explicitly included by Section 2(k) |
| Store room / utility inside the flat | Included | Enclosed usable area within the unit |
| External walls | Excluded | Structural envelope, not usable space |
| Balcony / verandah (exclusive) | Excluded | Named exclusion in Section 2(k) |
| Open terrace (exclusive) | Excluded | Named exclusion in Section 2(k) |
| Service & plumbing shafts | Excluded | Named exclusion in Section 2(k) |
| Lift lobby, staircase, corridor | Excluded | Common area, shared with the building |
| Clubhouse, gym, pool | Excluded | Common amenity, shared with the project |
| Car parking | Excluded | Separate allotment, charged separately |
Balconies and terraces are excluded from carpet area but are usually disclosed as a separate line in the agreement. Read that line — a large wraparound balcony has real value even though it does not count here.
Carpet area vs built-up vs super built-up
Six terms get used in Indian property listings, and they measure six different things. This is the table to keep.
| Term | What it measures | Internal walls | External walls | Balcony | Common areas | Typical size* |
|---|---|---|---|---|---|---|
| Carpet area (literal) | Floor you can lay a carpet on | No | No | No | No | ~810 sq ft |
| RERA carpet area (the legal one) | Net usable floor area per Section 2(k) | Yes | No | No | No | ~840 sq ft |
| Built-up area | Carpet + all walls + balcony | Yes | Yes | Yes | No | ~1,010 sq ft |
| Super built-up area | Built-up + share of lobbies, lifts, stairs, clubhouse | Yes | Yes | Yes | Yes | 1,200 sq ft |
| Saleable area | The number the builder prices against. Usually identical to super built-up. | Yes | Yes | Yes | Yes | 1,200 sq ft |
*On a flat advertised as 1,200 sq ft at a typical 30% loading factor. Actual figures vary by project and must be taken from the RERA-registered agreement, never from a brochure.
A builder may still advertise and price on super built-up area — RERA did not ban that. What RERA requires is that the carpet area is stated in the agreement for sale. If a project's paperwork does not disclose carpet area, that is a red flag serious enough to walk away from.
Loading factor
Loading factor is the gap between what you pay for and what you get, expressed as a percentage. It is the honest way to compare two projects.
The formula
Loading factor = (Super built-up area − Carpet area) ÷ Carpet area × 100
- Super built-up area
- 1,200 sq ft
- RERA carpet area
- 840 sq ft
- Difference
- 360 sq ft
- Loading factor
- 42.9%
In India, loading typically runs 25% to 40%. Older buildings with modest lobbies sit at the low end. New luxury towers with double-height entrances, sky lounges and large clubhouses sit at the high end — you are, quite literally, paying for the marble in the lobby.
Working out the real price per square foot
This is where carpet area stops being a definition and starts being money.
Two flats, same brochure price
Both advertised at 1,200 sq ft, ₹8,000 per sq ft. Both cost ₹96 lakh. They are not the same flat.
- Project A — loading 30%
- Carpet area
- 923 sq ft
- Total price
- ₹96,00,000
- Real rate per sq ft of carpet
- ₹10,401
- Project B — loading 45%
- Carpet area
- 828 sq ft
- Total price
- ₹96,00,000
- Real rate per sq ft of carpet
- ₹11,594
- You get 95 sq ft less in Project B
- for the same ₹96 lakh
Total price ÷ RERA carpet area = what you are actually paying per square foot.
Do it for every shortlisted project. Two flats advertised at the same rate can differ by ₹1,200 per square foot once you measure them against usable space. On a 900 sq ft flat, that is over ₹10 lakh.
How to measure carpet area yourself
- Get the RERA-approved floor plan from the state RERA portal, not from the sales office. Search the project's RERA registration number.
- Measure each enclosed room wall-to-wall — length × breadth, in feet. Bedrooms, living, dining, kitchen, bathrooms, internal utility.
- Add them up. That total is close to the literal carpet area.
- Add the internal partition walls if you want the RERA figure. Wall thickness × length, for every internal wall.
- Do not add the balcony, the open terrace, or anything outside your front door.
- Compare against the agreement. A variance of 1–2% is normal construction tolerance. More than that, ask.
If the constructed flat differs materially from the carpet area in the agreement, RERA gives you a remedy — you can seek a refund of the excess amount paid, with interest.
Four mistakes buyers make
1. Comparing brochure rates across projects
₹8,000 per sq ft at 30% loading and ₹8,000 per sq ft at 45% loading are not the same price. Compare rate per carpet square foot or you are comparing nothing.
2. Assuming carpet area is the same in every state
RERA's definition is central and uniform. But the way builders present it varies. Maharashtra's MahaRERA is generally the most rigorous. Read the agreement, not the marketing.
3. Forgetting balconies exist
They are excluded from carpet area — but a 100 sq ft balcony is real, usable, valuable space. Two flats with identical carpet areas can be very different homes.
4. Taking the number from the sales office
Take it from the RERA portal. It is free, it is public, and it is the number the builder is legally bound to.
Frequently asked questions
Is carpet area the same as RERA carpet area?
Not quite. The literal meaning of carpet area excludes all walls. RERA carpet area, defined in Section 2(k), includes internal partition walls while excluding external walls, shafts, balconies and open terraces. RERA's figure is usually 3–5% larger. When a builder quotes “carpet area” in an agreement, they mean the RERA definition.
Do builders have to show carpet area?
Yes. Since RERA came into force in May 2017, carpet area must be disclosed in the agreement for sale for any project that requires RERA registration. Builders may still advertise and price on super built-up area, but the carpet figure has to be in the paperwork. If it isn't, treat that as a serious warning sign.
What is a good loading factor?
Anything from 25% to 40% is normal in India. Below 30% is efficient. Above 40% usually means large lobbies, extensive amenities or a low-density tower — you get less flat but more building. Neither is objectively better; what matters is that you know the number and compare like with like.
Is the balcony included in carpet area?
No. An exclusive balcony or verandah is specifically excluded by Section 2(k), as is an exclusive open terrace. They are typically disclosed as a separate line item in the agreement.
How do I calculate the real price per square foot?
Divide the total price by the RERA carpet area. A ₹96 lakh flat with 840 sq ft of carpet costs ₹11,428 per usable square foot — not the ₹8,000 on the brochure, which was calculated against super built-up area.
What if the delivered flat is smaller than the carpet area in my agreement?
RERA provides a remedy. If the carpet area of the flat handed over is less than what was stated in the agreement, you are entitled to a refund of the excess amount paid, with interest. Raise it with the builder in writing first; if unresolved, you can file a complaint with your state RERA authority. Minor variance of 1–2% is usually within construction tolerance.
Is carpet area used to calculate maintenance charges?
It varies. Some societies charge maintenance per square foot of carpet area, others use super built-up. The agreement or the society bye-laws will specify which. Ask before you buy — on a large flat, the difference compounds over decades.