Carpet Area & Loading Calculator
Convert between carpet area, built-up area and super built-up area, work out the loading percentage, and see the real per-square-foot price you are paying.
💼 Are you a real estate agent or broker? Send this calculator to your buyers on your own branded listing page — every enquiry comes straight to your WhatsApp. Create free agent page →Builders quote super built-up area, but you live in the carpet area. The gap between them is called loading, and at 30% loading a "1,000 sq ft" flat gives you about 700 sq ft of usable floor.
Since RERA came into force in 2016, builders must disclose and sell on carpet area — defined as the net usable floor area within the walls, excluding the external walls, shaft, balcony and open terrace, but including internal partition walls. This calculator converts between the three and shows what you are really paying per usable foot.
The three areas
- Carpet area — net usable floor area inside the flat, excluding external walls, services shafts, exclusive balcony and open terrace, but including internal partition walls. This is the RERA definition and what you actually occupy.
- Built-up area — carpet area plus the thickness of walls and usually the balcony. Typically 10–15% above carpet.
- Super built-up area — built-up plus your share of common spaces: lobbies, staircases, lifts, clubhouse, gym. This is what builders historically priced on, and it has no legal definition.
Loading % = (super built-up ÷ carpet − 1) × 100
A worked example
A flat advertised as 1,000 sq ft super built-up at ₹8,000 per sq ft costs ₹80,00,000. At 30% loading the carpet area is 769 sq ft — so the real rate is ₹10,403 per usable square foot, and you are paying for 231 sq ft you cannot furnish. A competing project quoting ₹8,500 per sq ft at 18% loading is actually cheaper per usable foot.
What loading is reasonable
Typical loading runs 20–30%. Older buildings with minimal amenities can be under 20%; amenity-heavy towers with large clubhouses reach 35–40%. High loading is not automatically bad — you are buying the amenities — but it must be compared like for like, on carpet.
Under RERA, the builder must state carpet area in the agreement and advertise on it. If a sales team will only quote super built-up, ask for the carpet figure in writing before paying any token.
Turn a calculation into an enquiry
Buyers who run these numbers are ready to talk. Give every listing its own page with your photo, phone and WhatsApp on it — leads land straight on your phone.
Create your free property pageFrequently asked questions
What is carpet area as per RERA?
The net usable floor area within the apartment walls, excluding the area covered by external walls, service shafts, exclusive balcony or verandah and exclusive open terrace — but including the area of internal partition walls.
What is a good loading percentage?
20–25% is reasonable in most projects. Above 35% you are paying substantially for shared amenities, which is a fair trade only if you will actually use them.
Are builders allowed to sell on super built-up area?
They must disclose and contract on carpet area under RERA. Many still quote a super built-up rate in marketing, which is why converting to a per-carpet rate is the only way to compare projects honestly.
Is the balcony included in carpet area?
No. An exclusive balcony or verandah is excluded from RERA carpet area, though it is usually included in built-up area. Some states require it to be disclosed separately.
How do I compare two projects fairly?
Convert both to price per carpet square foot. A lower headline rate with heavy loading is frequently more expensive per usable foot than a higher rate with light loading.