Check Your Building's FSI Potential Before Inviting Bids
Knowing roughly what your plot can build is the difference between negotiating from facts and negotiating from hope.
What exactly is FSI?
FSI, or Floor Space Index, is the total floor area a building may have, divided by the area of the plot it stands on. That is how DCPR 2034 defines it for Greater Mumbai. More permitted floor area means more saleable flats — and it is that extra saleable area which pays for your bigger flats, your corpus and your rent during construction.
What decides how much your plot can take?
Everything here is specific to your address. The size and shape of the plot, the width of the access road, the zone, whether your building is cessed, and which incentive scheme applies — 33(7) and 33(7A) for cessed buildings, 33(7B) read with 20(B), 33(9) for cluster, 33(14) for slum. Fungible Compensatory Area under Regulation 31(3) and TDR under Regulation 32 can add more still. Anyone who quotes you one universal FSI number for all of Mumbai is guessing. Our DCPR 2034 guide explains these terms slowly.
The bands, so you can place your own plot
Your road width does most of the work. Sanctioned DCPR 2034 Table 12 sets permissible FSI in five bands, and the figures are published — you do not have to guess:
| Width of the access road | Island City | Suburbs & Extended Suburbs |
|---|---|---|
| Less than 9 m | 1.33 | 1.00 |
| 9 m and above, less than 12.00 m | 2.00 | 2.00 |
| 12.00 m and above, less than 18.00 m | 2.40 | 2.20 |
| 18.00 m and above, less than 27 m | 2.70 | 2.40 |
| 27 m and above | 3.00 | 2.50 |
Source: DCPR 2034 (sanctioned), Table 12. Each figure is the basic FSI plus the premium slice plus TDR.
Two numbers, and you have your envelope
FSI is applied to the net plot area, not the figure on your property card. Regulation 30(A)(2) requires you to deduct land under DP roads, any sanctioned Regular Line under the MMC Act, land under Regulation 16, Regulation 14 amenity plots, and Regulation 17 reservations to be surrendered. You get TDR for what you surrender, under Regulation 32.
Worked example — a suburban society
Plot on the property card: 2,000 sq m. Land to be surrendered for a DP road: 150 sq m.
Net plot under Reg 30(A)(2) = 2,000 − 150 = 1,850 sq m
Access road measured at 14 m → suburbs band 12.00 to <18.00 m → permissible FSI 2.20
Permissible built-up area = 1,850 × 2.20 = 4,070 sq m (about 43,810 sq ft)
Now move the same plot to a road of 8.5 m: FSI 1.00, so 1,850 sq m — 2,220 sq m less. That single measurement is worth more than any clause you will negotiate.
Run your own two numbers the same way, then ask every bidder to show their FSI working against them. A developer quoting the premium at 60% of the ASR rate is costing his project off the superseded draft and overstating his own expense by a fifth — which comes out of the surplus he offers you.
Why do this before inviting bids?
A society that does not know its own potential negotiates blind. If the committee has no rough idea of the envelope, a developer's offer of, say, 30 per cent extra area sounds generous — even when the plot could comfortably support more. A half-hour with the numbers changes the conversation: you can ask why an offer falls short of what the plot appears able to deliver, and judge every bid on the same basis.
Start with the FSI and feasibility calculator, then see what that could mean for your own flat in the additional area calculator. Treat both as indicative. The binding figure comes only from your architect's plans and the approvals your plot actually receives — but an indicative figure is still far better than none when the bids arrive.
Work it out for your own society
It gives your society an indicative FSI and buildable area for your own plot, road width and likely DCPR scheme.
Open the FSI & Feasibility CalculatorCommon questions
Is there one standard FSI for all Mumbai societies?
No. Under DCPR 2034, FSI is total floor area divided by plot area, and the permitted figure depends on your plot size, access road width, zone, cessed status and the applicable 33-series scheme. Fungible Compensatory Area and TDR can change it further. Any single number offered as universal for Mumbai should be treated with caution.
Can we simply rely on the developer's own FSI working?
You can read it, but verify it independently. Developers prepare their own feasibility, and their commercial interest lies in a conservative reading of what the plot can deliver. Run your own indicative working first, then ask each bidder to show the assumptions behind theirs, including road width, scheme, fungible area and TDR, and compare them side by side.
Do we need an architect before inviting bids?
Not necessarily at the very first stage. An indicative calculation is enough to frame the tender and read offers sensibly. Before you sign anything, though, appoint your own architect and legal adviser, since only sanctioned plans settle the actual buildable area. The Section 79A process and the Development Agreement should follow that professional advice.
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