One of these is defined by an Act of Parliament. The other is a builder's addition sum with no legal meaning at all. On a Pune 3 BHK the difference runs between 90 and 150 square feet — and almost every property portal prints the bigger number under the smaller number's name.
Last reviewed 14 September 2026.
If you are comparing two flats in Wakad or Warje and one says 1088 sq ft while the other says 990 sq ft, you may be looking at the same flat. Not a similar flat — the same one, measured two different ways by two different people who both think they are telling you the carpet area.
The number that matters legally is the one in your agreement for sale, in square metres. Everything else is a brochure.
“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”
Section 2(k), Real Estate (Regulation and Development) Act, 2016Two details in that definition do most of the work:
This is the figure a registered project must disclose on the MahaRERA portal, the figure the sanctioned plans carry, and the figure your agreement has to state. It is also, in Maharashtra, the only figure a builder may price a flat on.
It appears nowhere in the Act and nowhere in MahaRERA's rules. It is a measure developers construct themselves, and in Pune the construction is almost always:
usable carpet = RERA carpet + balcony + dry balcony (+ private garden, on ground-floor layouts)
There is nothing dishonest about publishing it. It answers a real question — how much floor do I actually get the use of — and a good brochure prints both columns side by side, which is exactly what Siddhashila's Treasure Troves brochure does.
The problem starts one step later. Because the term has no definition, nobody is obliged to compute it the same way, and nobody is obliged to label it. So it gets reprinted downstream as “carpet area”, and by the time it reaches a portal listing the label is wrong and there is no way to tell from the page.
| Measure | What it counts | Legal standing |
|---|---|---|
| RERA carpet | Floor inside the external walls, including internal partition walls. No balcony. | Defined in s.2(k). Must be disclosed and transacted on. |
| Usable carpet | RERA carpet + balcony + dry balcony (+ garden, sometimes). | None. Builder's own sum. |
| Built-up | Carpet + external and internal wall thickness + balcony. | No RERA definition. Typically 10–20% above carpet. |
| Super built-up | Built-up + your share of lobbies, stairs, lifts, club, services. | No RERA definition. Cannot be the basis of the sale. |
Before 2016 the industry sold on super built-up, which is why a 1,200 sq ft flat could have 750 sq ft of floor in it. RERA closed that door. “Usable carpet” is a much smaller step in the same direction, and it is the one still open.
We hold the launch brochure and the 23-page floor-plan set for Treasure Troves (MahaRERA P52100052582). The plan set states the formula outright, and the brochure prints both columns. Here they are together:
Scroll the table sideways to see every column →
| Layout | RERA carpet | Balcony | Dry balcony | Usable carpet | Gap |
|---|---|---|---|---|---|
| 2 RHK Luxe | 718 | 62 | 36 | 809 | 91 |
| 3 RHK Luxe | 850 | 62 | 36 | 948 | 98 |
| 3 RHK Luxe (garden) | 860 | 62 | 36 | 1010 | 150 |
| 3 RHK Opula | 990 | 62 | 36 | 1088 | 98 |
| 3 RHK Privè | not published | — | — | 1101 | — |
All figures in square feet. Source: Siddhashila launch brochure pp. 13–14 and the project floor-plan set.
Two of those rows do not add up. 718 + 62 + 36 is 816, not 809. 860 + 62 + 36 is 958, not 1010 — the 52 sq ft difference is almost certainly the private garden, which the brochure page does not give a column. We publish the developer's numbers as printed and say so rather than quietly correcting them, because the arithmetic is the developer's to explain.
Take the 3 RHK Opula at the developer's quoted ₹1.39 Cr. Divide by the number a portal gives you and divide by the number the plans give you:
| Divide ₹1.39 Cr by | Area | Rate you compute |
|---|---|---|
| “Carpet area” as portals publish it | 1088 sq ft | ₹12,776 / sq ft |
| RERA carpet area from the plans | 990 sq ft | ₹14,040 / sq ft |
A little under 10% — ₹1,264 per square foot — sitting between the rate you think you negotiated and the rate you are actually paying. That is the whole reason to care. It does not make the flat a bad buy. It makes every comparison you ran against another project slightly wrong, and in the same direction every time.
₹1.39 Cr is the figure Siddhashila's sales team quoted in September 2026 and we are still getting a dated cost sheet in writing. Their own September campaign prints the same number as an all-inclusive price, which would put the agreement value materially lower. We have not settled which reading is right, and we say so on the project page rather than picking the flattering one.
Ask by email or on WhatsApp, not on a phone call. A sales team that answers all four in writing is one you can hold to the answers. One that will not is telling you something too.
We are a channel partner, not a promoter, and our revenue comes from the developer — so take our word on nothing you can verify yourself. What we do commit to is printing both numbers on every listing, labelled, with the RERA figure first. You can see it on Treasure Troves, Wakad and on Royal Paradise, Warje. If a project's RERA carpet area is not published anywhere we can find, we say “not published” rather than substituting the usable figure.