Carpet Area Calculator
Carpet Area, Built-up Area and Super Built-up Area Calculator
Work out carpet, built-up and super built-up area from any one of them, and what a quoted price per square foot really costs per square foot of carpet area, the RERA measure.
Carpet, built-up and super built-up area
1,300 sq ft super built-up, walls 10%, loading 30% on carpet, $8,000 per sq ft of super built-up
From one area to the other two
- carpet
- net usable floor area inside the flat, as RERA s.2(k) defines it
- walls
- external walls, shafts and exclusive balcony, as a % of carpet
- loading
- the share of lobbies, stairs, lifts and amenities added on
- price per carpet sq ft
- total price ÷ carpet area
Worked example
1,300 sq ft super built-up, walls 10%, loading 30% on carpet, $8,000 per sq ft of super built-up
Carpet = 1,300 ÷ 1.30 = 1,000 sq ft
Built-up = 1,000 × 1.10 = 1,100 sq ft
Total price = 8,000 × 1,300 = $1,04,00,000
Per sq ft of carpet = 1,04,00,000 ÷ 1,000 = $10,400, and per sq ft of built-up $9,455
A price of 8,000 per sq ft of super built-up, per sq ft of carpet
| Loading on carpet | Carpet share of super built-up | Price per carpet sq ft |
|---|---|---|
| 20% | 83.3% | $9,600 |
| 25% | 80.0% | $10,000 |
| 30% | 76.9% | $10,400 |
| 35% | 74.1% | $10,800 |
| 40% | 71.4% | $11,200 |
| 50% | 66.7% | $12,000 |
What RERA defines, and what it does not
Carpet area is the one measure the law defines. Section 2(k) of the Real Estate (Regulation and Development) Act, 2016 calls it 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 including the area covered by the internal partition walls. Section 4(2)(h) requires a promoter registering a project to disclose the carpet area of the apartments for sale, with the balcony and terrace areas shown separately. The agreement-for-sale formats that state RERA rules prescribe then state the price for that carpet area, and provide for a refund if the built carpet area turns out smaller, or an extra charge if it is larger, with a limit on increases.
Built-up and super built-up area are not defined in the Act, and builders measure them differently. On this page, built-up is carpet area plus the walls, shafts and balcony you enter as a percentage. Super built-up then adds the loading, your share of lobbies, staircases, lift wells and amenities. Some builders quote loading on carpet area and some on built-up area, and 30% means different amounts in the two cases, so the calculator asks which. Resale flats and older projects are still often advertised per sq ft of super built-up area.
Compare flats on price per carpet sq ft. Two flats at the same price per super built-up sq ft can differ a lot in usable space: the table shows how the price per carpet sq ft rises with the loading. The wall and loading percentages are whatever the builder or the documents say; the calculator does not assume a typical figure, because there is none that holds across cities and projects. For the next steps, see the down payment calculator and the home loan eligibility calculator. This is arithmetic on the figures you enter, not financial advice.
Frequently asked questions
What is carpet area under RERA?
The net usable floor area of the apartment: it excludes external walls, service shafts, the exclusive balcony or verandah and the exclusive open terrace, and includes internal partition walls (RERA 2016, section 2(k)).
What is loading?
The extra area added to the flat’s own area to get super built-up area, for its share of common spaces such as lobbies, stairs and lifts. It is quoted as a percentage of carpet area or of built-up area; ask which.
How do I convert a super built-up price to a carpet area price?
Multiply the total price out, then divide by the carpet area. At $8,000 per super built-up sq ft and 30% loading on carpet, you pay $10,400 per carpet sq ft.
Does RERA say a flat must be sold on carpet area?
The Act requires the carpet area to be disclosed (section 4(2)(h)), and the agreement-for-sale formats under state RERA rules price the flat on its carpet area. Check the carpet area in your agreement rather than the advertised super built-up figure.
Related calculators
References
- Real Estate (Regulation and Development) Act, 2016, section 2(k) (carpet area) and section 4(2)(h) (disclosure of carpet area, exclusive balcony or verandah and open terrace areas); section 13 (agreement for sale).
- Karnataka Real Estate (Regulation and Development) Rules, 2017, rule 8A and Annexure A (agreement for sale: price for the carpet area; refund if the carpet area is reduced, extra charge only for an increase of up to 3%). Other states’ rules follow the same model.
- Supreme Court of India, Jaypee Kensington Boulevard Apartments Welfare Association v. NBCC (India) Ltd., 2021: homebuyers could not be charged for an arbitrary increase in the name of super built-up area.