Carpet Area vs Super Built-up Area: Loading and Price Sheets
Two flats advertised at 1,350 sq ft can differ by 150 sq ft of floor you can actually use. Here is how carpet, built-up and super built-up area relate, with the maths.
Put two 3 BHK brochures side by side and both may say 1,350 sq ft. Measure the rooms and one flat has about 1,000 sq ft of floor you can walk on while the other has 1,120. The difference is loading, and it's why the question of carpet area vs super built up area decides what you're really paying per square foot. The RERA Act settled the legal definition of carpet area in 2016. The older terms, built-up and super built-up, still turn up on price sheets, hoardings and resale listings, so you need to read all three.
What carpet area means under RERA
Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 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 and exclusive open terrace area, but includes the area covered by the internal partition walls of the apartment."
Break that down:
- Included: bedrooms, living and dining, kitchen, bathrooms, internal passages, and the footprint of internal walls between rooms.
- Excluded: the outer walls of the flat, service shafts, and balconies or terraces meant only for your use.
Balconies aren't lost; the Act simply counts them separately. The builder must disclose the carpet area of each apartment type and, alongside it, the areas of exclusive balconies and terraces when registering the project. Your agreement for sale must state the carpet area, and that's the figure you can hold the builder to.
One thing people get wrong: carpet area under RERA is not the same as the area you'd get by adding up room sizes from the floor plan. Room dimensions usually leave out the internal walls, which RERA carpet area includes. Expect the RERA figure to be a little higher than your own sum of rooms.
Built-up area
Built-up area has no definition in the RERA Act. In common use it means carpet area plus the thickness of external walls, plus balconies (and sometimes shafts). Some builders count half of a balcony, some the whole. Because there's no single rule, treat any built-up figure as the builder's own measure and ask how it was worked out.
Super built-up area and the loading percentage
Super built-up area, often called super area or saleable area, adds your proportionate share of common spaces to the built-up area: lobbies, staircases, lift wells, corridors, and in many projects a share of the clubhouse, guard rooms and other amenities.
The loading percentage is how much bigger the super area is than the carpet area:
Loading = (super built-up area minus carpet area) divided by carpet area.
Some developers work loading on built-up area rather than carpet area. Ask which, because it changes the number. For comparisons, always calculate against RERA carpet area.
A worked example
Take a 3 BHK on the 12th floor of a high-rise:
| Component | Area (sq ft) |
|---|---|
| RERA carpet area (rooms, kitchen, baths, internal walls) | 1,000 |
| External walls and shafts | 80 |
| Exclusive balconies | 90 |
| Built-up area | 1,170 |
| Share of lobbies, stairs, lifts, corridors | 120 |
| Share of clubhouse and amenities | 60 |
| Super built-up area | 1,350 |
Loading here is 350 divided by 1,000, or 35%. Nothing about that is unlawful, but it means 26% of the area you are "buying" on a super-area price sheet isn't inside your front door.
The figures are illustrative. Loading varies by project and depends on tower height, the number of flats per floor, and how much clubhouse and podium space is shared out.
Carpet area vs super built-up area on a price sheet
Here's where it pays off. Suppose you're choosing between two projects in the same area.
| Project A | Project B | |
|---|---|---|
| How the price is quoted | ₹7,500 per sq ft on super area | ₹9,800 per sq ft on carpet area |
| Super built-up area | 1,350 sq ft | 1,380 sq ft |
| RERA carpet area | 1,000 sq ft | 1,040 sq ft |
| Base price | ₹1.01 crore | ₹1.02 crore |
| Effective rate on carpet area | ₹10,125 per sq ft | ₹9,800 per sq ft |
Project A looks cheaper at ₹7,500 against ₹9,800. It isn't. Per square foot of usable floor, B costs ₹325 less, and you get 40 sq ft more to live in for roughly the same money.
The method works for any pair of listings:
- Get the RERA carpet area for the exact unit in writing. It's in the agreement for sale and usually in the project's RERA record.
- Take the total base price, including PLC and floor rise if they're compulsory for that unit.
- Divide price by carpet area. That's the number to compare.
- Look at balcony and terrace areas separately. A large usable balcony has value, but it shouldn't be priced as if it were a bedroom.
If you're converting between sq ft, sq m and sq yd while you do this, the area converter saves some arithmetic.
When the carpet area shrinks at possession
Final carpet area can differ from the agreed figure once the building is finished and measured. The agreement for sale usually says how that is handled: a refund at the agreed rate if the area falls, and a limit on how much you can be charged if it rises. Read that clause before signing, and ask for the measured carpet area in writing at possession. If the shortfall is large, the RERA authority is where you take it. Measuring is simple enough to do yourself with a laser meter: take each room wall to wall, add the internal walls, and compare.
Reading listed rates carefully
Per-sq-ft rates you see quoted for a locality mix both kinds of figures. On IndiProp, for example, the indicative median rate for Sector 150, Noida is about ₹15,000 per sq ft and for Thanisandra, Bengaluru about ₹13,600, worked out from listed unit prices and sizes on projects listed in September 2026. They're useful for ranking localities, not for judging one flat. For that, you need the carpet-area rate of the unit you're offered.
Resale listings are the trickiest. Older flats, sold before 2017, were often registered on super area, and owners still quote it. Ask for the carpet area in the original agreement, or measure it.
Questions to put to the sales team
- What is the RERA carpet area of this exact unit, and what are the balcony and terrace areas.
- Is the price quoted on carpet or super area, and what's the loading.
- Which common areas are included in super area. Is the clubhouse counted.
- What happens if the final carpet area is smaller than agreed. Get the adjustment clause in the agreement.
Ask for the price sheet in writing with carpet area printed on it. If a builder won't put carpet area on paper, that tells you how the rest of the negotiation will go.
Once you've got the true rate, run the loan maths in the home affordability calculator and compare against projects in Bengaluru or Noida with a like-for-like figure. Projects such as TVS Auralis in Thanisandra show the RERA number on their IndiProp page, so you can check the declared carpet areas on the Karnataka RERA portal.
Frequently asked questions
What is carpet area as per RERA?
Section 2(k) of the RERA Act defines it as the net usable floor area of an apartment, excluding external walls, service shafts and exclusive balconies or terraces, but including internal partition walls. It is the area the builder must state in the agreement for sale.
How do I calculate loading percentage?
Subtract the carpet area from the super built-up area and divide by the carpet area. A flat with 1,000 sq ft carpet and 1,350 sq ft super area has 35% loading.
Is a balcony included in carpet area?
No. Under RERA, exclusive balcony, verandah and open terrace areas are excluded from carpet area and disclosed separately.
Can a builder sell on super built-up area after RERA?
Builders must disclose carpet area in the RERA registration and the agreement for sale. Many still quote super area on marketing material, so convert every price to a rate per square foot of carpet area before comparing.
Sources: Real Estate (Regulation and Development) Act, 2016 (India Code) · IBC Laws: Section 2 of the RERA Act, definitions · Karnataka RERA
