Three areas, three different numbers, and plenty of confusion — especially when a contractor's per sq ft rate meets an architect's area statement. Knowing which is which keeps quotes comparable.
The Three Areas
| Area | Includes | Used for |
|---|---|---|
| Carpet | Usable floor inside the unit, including internal partitions | Flats sold under RERA; comparing usable space |
| Built-up (plinth) | Carpet + wall thickness (+ balconies, traditionally) | Construction cost of houses; building rules |
| Super built-up | Built-up + share of common areas | Apartment pricing (pre-RERA practice) |
What Does RERA Say?
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 external walls, service shafts, exclusive balconies or verandahs and exclusive open terraces, but including the area covered by internal partition walls. Apartments must be sold on carpet area.
For an independent house you build yourself, RERA's definition is a useful reference, but the number that matters for your budget is built-up area.
Why Built-Up Area Drives Cost
Walls, columns and their foundations cost money to build. That is why construction is quoted on built-up area: it is the whole covered floor you are paying to construct. Two practical points:
- Ask how it is measured. Is the staircase counted on every floor? Balconies at full or half area? The stair headroom on the terrace?
- Compare like with like. A lower per sq ft rate on a generously measured area can cost more than a higher rate on a strict one.
Typical Ratios
| From | To | Typical ratio |
|---|---|---|
| Built-up | Carpet | Carpet ≈ 75–85% of built-up |
| Plot | Built-up per floor (small plots, after setbacks) | ≈ 60–70% of plot area |
Thicker walls (9 inch rather than 6 or 4 inch AAC partitions) and more rooms reduce carpet area for the same built-up area.
How to Measure Built-Up Area
- Measure each floor's outer dimensions, to the outside face of external walls.
- Calculate the floor area, subtracting open cut-outs such as a double-height space.
- Add balconies and the stair as your contract defines.
- Sum all floors.
The Short Version
Carpet is what you live in; built-up is what you build and pay a contractor for; super built-up is an apartment concept. Agree in writing how built-up area is measured before you compare per sq ft quotes.
