Area & Measurement
Carpet Area vs Built-Up Area vs Super Built-Up Area
Five numbers, one flat. Only one of them has legal force, and it isn't the one on the brochure.
The short answer
Carpet area is what you can use. Built-up area adds the walls and balcony. Super built-up area adds a share of the lobby, lifts and clubhouse — and that's the number on the brochure.
The gap between the first and the last is the loading factor, typically 25–40%. It means a flat sold as 1,200 sq ft may give you around 840 sq ft to live in — and the real price per square foot is roughly 40% higher than advertised.
The comparison table
Keep this one. It is the whole of it.
| Term | What it measures | Internal walls | External walls | Balcony | Common areas | Typical size* |
|---|---|---|---|---|---|---|
| Carpet area (literal) | Floor you can lay a carpet on | No | No | No | No | ~810 sq ft |
| RERA carpet area (the legal one) | Net usable floor area per Section 2(k) | Yes | No | No | No | ~840 sq ft |
| Built-up area | Carpet + all walls + balcony | Yes | Yes | Yes | No | ~1,010 sq ft |
| Super built-up area | Built-up + share of lobbies, lifts, stairs, clubhouse | Yes | Yes | Yes | Yes | 1,200 sq ft |
| Saleable area | The number the builder prices against. Usually identical to super built-up. | Yes | Yes | Yes | Yes | 1,200 sq ft |
*On a flat advertised as 1,200 sq ft at a typical 30% loading factor. Actual figures vary by project and must be taken from the RERA-registered agreement, never from a brochure.
What each one actually means
Carpet area — what you can use
The floor you could lay a carpet across. Excludes every wall, because you can't carpet a wall. This is the everyday meaning of the term.
RERA carpet area — the legal one
Defined in Section 2(k) of the RERA Act, 2016. Net usable floor area, excluding external walls, service shafts, exclusive balconies and open terraces — but including internal partition walls.
RERA carpet area includes internal walls. Literal carpet area excludes them. They are different numbers, and RERA's is larger — usually by 3–5%.
When a builder writes 'carpet area' in an agreement, they mean the RERA definition. Plan your furniture against slightly less.
Built-up area — the engineering number
Carpet area plus all walls plus the balcony. It's the full footprint your flat occupies on the floor plate. Typically 10–20% more than carpet area. Honest, but not useful for comparing projects.
Super built-up area — the brochure number
Built-up area plus your proportionate share of the common areas: lobbies, staircases, lifts, corridors, clubhouse, gym, pool. Typically 25–40% more than carpet area. This is what you are advertised, and usually what you are priced on.
Saleable area — the billing number
Whatever the builder multiplies the rate by. Usually identical to super built-up area. Has no statutory definition, so confirm its composition in writing.
The loading factor connects them
The formula
Loading factor = (Super built-up − Carpet area) ÷ Carpet area × 100
- Super built-up area
- 1,200 sq ft
- RERA carpet area
- 840 sq ft
- Difference
- 360 sq ft
- Loading factor
- 42.9%
25–40% is the normal Indian range. Below 30% is efficient. Above 40% means large lobbies and heavy amenities — a legitimate trade, provided you know you're making it.
What the difference actually costs
This is where the table stops being trivia.
Two flats. Identical brochures.
Both advertised at 1,200 sq ft, ₹8,000 per sq ft. Both ₹96 lakh.
- Project A — loading 30%
- Carpet area
- 923 sq ft
- Total price
- ₹96,00,000
- Real rate per usable sq ft
- ₹10,401
- Project B — loading 45%
- Carpet area
- 828 sq ft
- Total price
- ₹96,00,000
- Real rate per usable sq ft
- ₹11,594
- 95 sq ft less flat
- for the same ₹96 lakh
The brochures are identical. The flats differ by a study.
Which one is legally binding?
| Measurement | Defined in law? | Must the builder disclose it? |
|---|---|---|
| Carpet area (literal) | No | No |
| RERA carpet area | Yes — Section 2(k) | Yes — in the agreement for sale |
| Built-up area | No | No |
| Super built-up area | No | No |
| Saleable area | No | No |
| Loading factor | No | No — you calculate it yourself |
One row in this table has legal force. If a RERA-registered project's agreement does not disclose the carpet area, the builder is in breach — and that is a reason to walk away, not to negotiate.
How to use this
- Get the RERA carpet area for every shortlisted project — from the state RERA portal, not the sales office.
- Divide the total price by it. That's your real rate per usable square foot.
- Compare those numbers. Never the brochure rates.
- Then judge the loading. Walk the lobby and the clubhouse. Decide whether what you're paying for is worth having.
Total price ÷ RERA carpet area = what you are actually paying per square foot.
Two flats advertised at the same rate can differ by ₹1,200 per usable square foot. On a 900 sq ft flat, that is over ₹10 lakh.
Frequently asked questions
What is the difference between carpet area and built-up area?
Carpet area is the usable floor space inside your flat. Built-up area adds the walls and the balcony on top of it — typically 10% to 20% more. Built-up area tells you how much floor plate your flat occupies; carpet area tells you how much of it you can live in.
What is the difference between built-up and super built-up area?
Super built-up area takes the built-up area and adds your proportionate share of the building's common areas — lobbies, staircases, lifts, clubhouse. Super built-up is always the largest figure and is usually the one on the brochure.
Which area is used for pricing?
In most Indian projects, the super built-up area (often called saleable area). That is why the advertised rate per square foot is misleading — it is calculated against a number roughly 30% to 40% larger than the space you can actually use.
Which area figure is legally binding?
Only the RERA carpet area. Section 2(k) of the RERA Act defines it, and it must be disclosed in the agreement for sale. Built-up, super built-up and saleable area have no statutory definition at all.
How much smaller is carpet area than super built-up area?
Typically 25% to 40% smaller. A flat advertised as 1,200 sq ft super built-up will usually have somewhere between 860 and 960 sq ft of RERA carpet area, depending on the loading factor.
Is a high loading factor a scam?
No. It is a trade — less flat, more building. A 45% loading may buy a genuinely excellent clubhouse, faster lifts and a grander lobby. The problem was never the trade; it was that buyers made it without being told the terms. Now you can find out, so find out.