Carpet area calculator: super built-up to carpet area and back
Flats in India are advertised with three different areas. The carpet area is the floor you can actually use, the built-up area adds the walls and your balcony, and the super built-up area (sometimes called saleable area) adds a share of the lobbies, staircases, lifts and amenities. This carpet area calculator converts between all three from whichever figure you have, using the loading percentage, the wall allowance and the balcony area, and shows each step of the arithmetic.
It then converts the price into a rate per carpet square foot, which is the fairest way to compare flats with different loadings, and lets you compare two flats side by side. It works in square feet or square metres and runs in your browser. The results are estimates: the carpet area stated in the project’s RERA registration and in your agreement for sale is what counts.
How to use the Carpet Area Calculator
- Choose what you know in I know the — usually the super built-up area from a brochure — and type the Area in sq ft or sq m.
- Enter the builder’s Loading and whether it is a percentage of the carpet or the built-up area.
- Adjust External walls and shafts and the Exclusive balcony / terrace area if you know them; the defaults are only examples.
- Read the RERA carpet area, built-up and super built-up areas and the step-by-step breakdown.
- Under Price per square foot, enter the quoted rate or total price to see what you pay per carpet unit, and fill in Compare two flats to rank two offers.
Carpet Area Calculator features
Converts in every direction
Start from carpet, built-up or super built-up area; the other two are worked out with the same assumptions.
RERA-consistent carpet area
Carpet area includes internal partition walls and excludes external walls, shafts and exclusive balconies or terraces, as the 2016 Act defines it.
Loading on carpet or built-up
Builders quote loading both ways; pick the one in your quote and the tool also reports loading over carpet and carpet efficiency.
Price per carpet sq ft
Turns a super built-up rate or total price into the price of usable floor, and compares two flats.
What RERA says carpet area is
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.” An exclusive balcony, verandah or open terrace is one attached to the apartment for the allottee’s exclusive use. Source: the Act as published on India Code (indiacode.nic.in), checked October 2026.
So RERA carpet area is slightly larger than the older “wall-to-wall” carpet measurement, because internal walls count. RERA registration documents and sale agreements state the apartment’s carpet area on this basis; balconies and terraces are listed separately, and super built-up area is not a RERA figure at all.
Formulas used
Example: a 1,250 sq ft super built-up flat with 30% loading on carpet has 1,250 ÷ 1.3 = 961.5 sq ft of carpet area. At ₹9,500 per super built-up sq ft (₹1.19 crore), you are paying about ₹12,350 per carpet sq ft.
| From | Formula |
|---|---|
| Carpet → built-up | built-up = carpet × (1 + walls %) + balcony |
| Carpet → super built-up (loading on carpet) | super = carpet × (1 + loading %) |
| Built-up → super built-up (loading on built-up) | super = built-up × (1 + loading %) |
| Super built-up → carpet (loading on carpet) | carpet = super ÷ (1 + loading %) |
| Loading over carpet | (super − carpet) ÷ carpet × 100 |
| Price per carpet unit | total price ÷ carpet area |
Tips before you sign
- Ask for the RERA carpet area in writing and check it against the registration on your state RERA website.
- Compare flats on price per carpet sq ft; a low super built-up rate can hide a high loading.
- Wall thickness and balcony sizes differ between projects; use the floor plan figures when you have them.
- Convert sq m, sq yd or local units with the area converter, then estimate stamp duty with the stamp duty calculator.
Carpet Area Calculator FAQ
How do I calculate carpet area from super built-up area?
Divide the super built-up area by (1 + loading %) when the loading is quoted on carpet area: 1,250 sq ft at 30% loading gives 961.5 sq ft. If the loading is on built-up area, divide to get built-up, then remove the balcony and wall allowance. The carpet area calculator handles both.
What is the usual carpet area to built-up area ratio?
Built-up area is carpet area plus external walls, shafts and any exclusive balcony, so the ratio depends on wall thickness and balcony size. Enter your floor plan figures for a project-specific answer.
What is RERA carpet area?
The net usable floor area of the apartment including internal partition walls, but excluding external walls, service shafts and exclusive balconies, verandahs and open terraces — section 2(k) of the RERA Act, 2016.
What is loading in real estate?
Loading is the extra area added to your flat for its share of common areas such as lobbies, staircases, lifts and the clubhouse. It is the gap between super built-up and carpet (or built-up) area, expressed as a percentage.
Is a balcony included in carpet area?
Not under RERA. An exclusive balcony, verandah or open terrace is listed separately; it is part of built-up area.