Carpet area vs built-up area vs super built-up area: what you actually get
The three areas on an Indian flat's price sheet mean very different things. Here is what each one counts, the typical loading, how RERA changed it, and how to check a floor plan yourself.
· 4 min read · 544 views · by the Cortex Digital Hub team
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Every flat in India is sold with three numbers that sound alike and mean very different things. Buyers compare projects on the wrong one, agents quote whichever is convenient, and the floor plan on the brochure rarely says which it is showing. This is the version you can carry into a sales office.
The three areas, in one table
| Term | What it counts | Typical share |
|---|---|---|
| Carpet area | Floor you can walk on inside the flat: rooms, kitchen, toilets, passages, internal walls. Not balconies, not external walls. | 100 (base) |
| Built-up area | Carpet area plus the external walls, plus balconies and verandahs. | 110–120 |
| Super built-up area | Built-up area plus your share of common spaces: lift lobby, staircases, corridors, clubhouse, gym, sometimes the swimming pool deck. | 125–140 |
The gap between carpet and super built-up is called loading. A project that says "25% loading" is telling you that a quarter of what you pay for is outside your front door.
What RERA changed
Before 2016, "carpet area" was whatever the developer's brochure said, and super built-up could stretch to include the garden and the security cabin. The Real Estate (Regulation and Development) Act fixed a single definition: carpet area is the net usable floor area of the apartment, including the area covered by internal partition walls, excluding external walls, service shafts, exclusive balconies or verandahs, and exclusive open terraces. Every RERA-registered project must state this number in the agreement, and the price in the agreement has to be based on it.
In practice brochures still lead with super built-up area because it is the bigger number. The RERA carpet area is usually in the price sheet or the cost sheet, sometimes on the last page. Ask for it first.
A worked example
A 3 BHK is advertised as 1,650 sq ft at ₹7,500 per sq ft, so ₹1.24 crore.
- Super built-up area: 1,650 sq ft
- Built-up area: about 1,420 sq ft
- RERA carpet area: about 1,250 sq ft
The same money on carpet area is ₹9,900 per sq ft. If the project next door advertises 1,550 sq ft at ₹7,800 but has 22% loading, its carpet area is about 1,270 sq ft at ₹9,500 per sq ft, and it is the cheaper flat despite the higher headline rate.
How to check the floor plan yourself
Most brochure plans print the room sizes: "BED ROOM 12'0" × 11'6"", "LIVING 12'0" × 27'3"". Multiply each pair, add them up, add the toilets, passage and kitchen, and you have a rough carpet area. It will be a little lower than the RERA figure because the printed sizes are measured wall to wall and the RERA figure includes the partition walls.
If the total you get is 1,180 sq ft and the sheet says 1,250, that is a normal difference. If it says 1,400, something else is being counted.
A furnished 3D view is the quickest way to feel the difference between the numbers. A 12' × 11'6" bedroom reads as a number on paper; with a queen bed, two side tables and a wardrobe drawn to scale it reads as "tight but fine" or "no space for the study table" in one look. The 2D to 3D floor plan converter keeps every printed size exactly where the plan has it, so the furniture is honest about the room.
Questions to ask in the sales office
- "What is the RERA carpet area, and what is the rate on it?"
- "What is the loading percentage, and what does it include?" (Clubhouse and pool are fair; parking and the security cabin are not.)
- "Is the balcony area shown separately in the agreement?"
- "Does the plan on the brochure show carpet dimensions or centre-line dimensions?" Centre-line (measured to the middle of the wall) makes rooms look 4–9 inches bigger each way.
Where buyers get caught
- Comparing rates across projects on different areas. Always convert to carpet.
- Assuming the balcony is part of the room size. On the plan it often looks continuous with the bedroom.
- Reading the plan at the wrong scale. A brochure page is shrunk to fit; a 5'0" balcony and a 3'0" passage can look the same width. The printed numbers are the truth, not the drawing.
- Treating the 3D render in the brochure as a measurement. Those renders are made for mood; furniture is often drawn small to make rooms look big. A render made from the plan itself, with the sizes locked, does not have that problem.
If you are a developer or agent, the same logic works in your favour: a 3D view that is visibly honest about room sizes builds more trust than a bigger super built-up number, and it is the kind of thing buyers forward to family on WhatsApp.
Frequently asked questions
Which area does the price per square foot apply to?
Most developers quote the rate on super built-up area, which is why two flats with the same carpet area can differ by 10–20% in price. Ask for the rate on RERA carpet area to compare like with like.
What is a normal loading percentage?
In most Indian cities super built-up area is 20–35% more than carpet area. Above 40% is high and worth questioning; below 15% is rare in apartment projects with lifts, lobbies and clubhouses.
Is the balcony part of the carpet area?
Under RERA, no. Carpet area is the usable floor area inside the walls of the flat, including internal partition walls, but excluding external walls, balconies, verandahs and open terraces. Balconies are listed separately.
Can I measure the carpet area from the floor plan?
Yes, roughly. Add up the printed room sizes (length × width) for every room inside the flat, including passages and toilets, and compare the total with the carpet area on the sheet. A gap of a few percent is normal; a gap of 15% is not.