Buying a flat quoted in super built-up area? Enter the area and the builder’s loading to get the carpet area you can actually use, the built-up area, and the real price per carpet sq ft. Compare two flats side by side and see which BHK the carpet area fits. Part of our free home planning tools.
How to use the carpet area calculator
- Choose which area you know: super built-up, built-up or carpet, and enter it in sq ft, m² or sq yd (gaj).
- Enter the builder’s loading (how much the super built-up area exceeds the carpet area). 25–40% is common; ask the builder.
- Optionally open Walls and balcony to adjust the wall share or add an exclusive balcony.
- Enter the rate per sq ft and what it is quoted on to see the total price and the price per carpet sq ft.
- Tick Compare with another flat to see which one gives more usable space for the money.
Carpet Area Calculator
Carpet, built-up and super built-up area, loading, and the real price per usable sq ft
Walls and balcony
Flat A vs flat B
What this means
Estimate. Builders and states measure these areas differently, and loading is whatever the builder applies. For a RERA-registered project, rely on the carpet area in the agreement and on the RERA website, not on this estimate.
Carpet, built-up and super built-up area
| Area | What it includes | Typical size vs carpet |
|---|---|---|
| Carpet area (RERA) | Net usable floor area inside the flat, including internal partition walls; excludes external walls, service shafts, exclusive balconies or verandahs and open terraces. | 100% |
| Built-up area | Carpet area + external walls and ducts + exclusive balcony. | About 110–120% |
| Super built-up area | Built-up area + a share of common areas: corridors, staircases, lifts, lobby, clubhouse. | About 125–140% (the loading) |
The carpet area definition is from Section 2(k) of the Real Estate (Regulation and Development) Act, 2016. For a detailed explanation with diagrams, read our guide on carpet area vs built-up area vs super built-up area.
Formulas
- Carpet area from super built-up: carpet = super built-up ÷ (1 + loading). Example: 1300 ÷ 1.30 = 1000 sq ft.
- Super built-up from carpet: super built-up = carpet × (1 + loading). Example: 1000 × 1.30 = 1300 sq ft.
- Built-up from carpet: built-up = carpet × (1 + wall share) + balcony. Example: 1000 × 1.12 + 50 = 1170 sq ft.
- Price per carpet sq ft: total price ÷ carpet area. Example: ₹8,000 × 1300 = ₹1.04 crore, which is ₹10,400 per carpet sq ft.
Why compare flats on carpet area
Two flats quoted at the same super built-up area can differ by 100 sq ft or more in usable space if their loading differs. In the tool’s example, flat A (1300 sq ft at 30% loading, ₹8,000 per sq ft) gives 1000 sq ft of carpet at ₹10,400 per carpet sq ft. Flat B (1250 sq ft at 35% loading, ₹7,800 per sq ft) looks cheaper but gives 926 sq ft at ₹10,530 per carpet sq ft. Since RERA, registered projects must state the carpet area, so ask for it and compare on that.
Frequently asked questions
How do I calculate carpet area from super built-up area?
Divide the super built-up area by 1 plus the builder’s loading. With 30% loading, a 1300 sq ft super built-up flat has 1300 / 1.30 = 1000 sq ft of carpet area. Ask the builder for the loading or, better, the RERA carpet area.
How do I convert carpet area to built-up area?
Built-up area is the carpet area plus the area under the external walls and ducts (usually 10 to 15 percent) plus any exclusive balcony. A 1000 sq ft carpet flat with 12% walls and a 50 sq ft balcony has about 1000 x 1.12 + 50 = 1170 sq ft built-up.
What is carpet area as per RERA?
Under Section 2(k) of the Real Estate (Regulation and Development) Act, 2016, carpet area is the net usable floor area of an apartment. It includes the area under internal partition walls and excludes the area under external walls, service shafts, exclusive balconies or verandahs and exclusive open terraces.
What is loading in a flat?
Loading is how much the super built-up area is larger than the carpet area, because it adds walls, balconies and a share of common areas such as lobbies, stairs, lifts and the clubhouse. It is often 25 to 40 percent in Indian apartments; a higher loading means less usable space for the same quoted area.
What is the difference between built-up area and super built-up area?
Built-up area is the flat itself: the carpet area plus its walls and exclusive balcony. Super built-up area adds a share of the building’s common areas, such as corridors, staircases, lift shafts, lobbies and amenities.
Should I compare flats on carpet area or super built-up area?
Compare on carpet area and on the price per carpet sq ft. Two flats with the same super built-up area can differ by 100 sq ft or more in usable space if their loading differs. RERA-registered projects must state the carpet area.
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Sources and limitations
The carpet area definition follows Section 2(k) of the Real Estate (Regulation and Development) Act, 2016. Loading and wall shares vary by project and builder; the tool applies the figures you enter. It is not legal or financial advice. Report errors via our Corrections Policy; see our Editorial Policy and Methodology.
Disclaimer: Online educational publication only. Not a substitute for legal, financial or professional advice. Full disclaimer · contact@speakarch.com
Last updated: 8 November 2026