Quick answer
Carpet area is the usable floor inside your home's external walls — the number RERA uses. Built-up adds the external walls and balconies; super built-up adds a share of lobbies, lifts, clubhouse and other common areas. Gujarat developers historically loaded super built-up 40–48% over carpet, so always compare homes — and prices per sq ft — on carpet area.
The three areas, defined
| Carpet area | Built-up area | Super built-up area | |
|---|---|---|---|
| What it measures | Usable floor inside external walls, incl. internal walls | Carpet + external walls + exclusive balcony/terrace | Built-up + share of common areas |
| Legal definition | Yes — RERA s.2(k) | No statutory definition | No statutory definition |
| Used by RERA | Yes | No | No |
| Typical share | Base | About 10–15% more than carpet* | About 30–48% more than carpet |
*Varies with wall thickness and balcony size — measure, don't assume.
RERA's definition, word for word
“carpet area” means 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.
The Act's explanation adds that an "exclusive" balcony, verandah or terrace is one appurtenant to your home and meant for your exclusive use. Common areas — staircases, lifts, lobbies, basements, parking, water tanks, community facilities — are defined separately (section 2(n)) and never form part of carpet area.
What counts and what doesn't
| Part of the home | In carpet area? | Where it shows up |
|---|---|---|
| Rooms, kitchen, toilets, internal passages | Yes | Carpet |
| Internal partition walls | Yes | Carpet |
| External walls (and columns within them) | No | Built-up |
| Service shafts | No | Built-up |
| Exclusive balcony / verandah / deck | No | Shown separately in RERA unit table |
| Exclusive open terrace | No | Shown separately |
| Wash / utility area | Check your agreement | Depends on design and enclosure |
| Lobby, lift, staircase, clubhouse | No | Super built-up (common areas) |
Gujarat RERA Circular 3/2017
On 14 August 2017 Gujarat RERA clarified how walls are treated: "walls" include RCC, concrete, shear, brick, block, precast and dry walls, together with columns inside or adjoining them. Walls on the outer face of the unit are external (excluded); walls inside the unit are internal partitions (included). This is why two homes with the same room sizes can show different carpet areas.
Loading factor: the formula
Loading % = (super built-up − carpet) ÷ carpet × 100
Carpet = super built-up ÷ (1 + loading)
| Super built-up (sq ft) | Carpet at 30% loading | At 40% | At 48% |
|---|---|---|---|
| 1,500 | 1,154 | 1,071 | 1,014 |
| 2,500 | 1,923 | 1,786 | 1,689 |
| 4,000 | 3,077 | 2,857 | 2,703 |
Loading in Gujarat, then and now
Before RERA, Gujarat projects were sold on super built-up area. CREDAI Ahmedabad's president, quoted by Gujarat Samachar in December 2023, said the loading was "vaguely calculated" at about 40%, 45% or 48% in different places — a single source, so treat it as indicative. Nationally, ANAROCK found average loading rose from 31% in 2019 to 40% in Q1 2025, ranging from 36% (Chennai) to 43% (Mumbai region). RERA registration now puts the carpet area of every unit on record, which is how we list the homes on this site.
The price-per-sq-ft trap
A home quoted at "₹10,000 per sq ft" on 2,500 sq ft super built-up costs ₹2.5 crore. At 40% loading its carpet is about 1,786 sq ft — ₹14,000 per sq ft of usable space. When you compare two projects, divide each total price by RERA carpet area. Our 4 BHK, 5 BHK and budget pages do exactly that for every home we represent.
Checking carpet area at site
- Ask for the RERA unit table and the unit's dimensioned floor plan.
- Confirm the agreement for sale states carpet area as defined in section 2(k), and lists balcony and terrace areas separately.
- At possession, measure room by room wall-to-wall, including internal walls.
- Add the areas; compare with the agreement. Record any shortfall in writing before signing the possession letter.
- Keep the measurements with your possession documents.
Next: hidden charges when buying a flat — the costs that sit on top of the per-sq-ft price.
Sources
- RERA Act, 2016 — section 2 definitions (Indian Kanoon)
- Gujarat RERA Circular 3/2017 — calculation of carpet area (IBC Laws) — 14 Aug 2017
- Gujarat Samachar — RERA carpet area to take over for Ahmedabad builders — 30 Dec 2023
- Business Standard — Super built-up vs carpet gap rises to 40%: ANAROCK — 9 Jun 2025
Last reviewed 29 Sep 2026 by the Surat Niwas research desk under our editorial policy. This guide is general information, not legal, tax or investment advice — confirm figures with the official portal, your bank or your advocate before you act.