How much does buying extra area from the builder really cost?
The rate the builder quotes is rarely the final figure you end up paying for extra area.
Many members take 100 to 200 sq.ft. over and above their entitled flat. It is often a sensible decision. But the price quoted in the meeting is only the starting point, and the difference between the quoted amount and the amount actually paid can be large.
Is the rate on carpet area or built-up area?
This is the commonest overcharge, and it is quiet. A rate applied to built-up area instead of RERA carpet area means you pay for a bigger number of square feet than you can actually use. Under RERA 2016, carpet area is the net usable floor area, excluding external walls, shafts and the exclusive balcony, verandah or open terrace, but including internal partition walls. The sale agreement must state carpet area. Before you agree to anything, run both figures through our carpet to built-up converter so you can see exactly what the gap costs you. If you are still deciding how much extra to take, the additional area calculator helps you size it first.
Price the whole package, not the rate
The quoted rate per square foot is only the first line. What leaves your bank account is the rate plus tax plus duty plus registration — and members routinely budget for the first and get surprised by the rest.
Worked example — buying 18 sq m of extra area
Extra area purchased: 18 sq m (about 194 sq ft) at Rs 2,20,000 per sq m.
Base consideration = 18 × 2,20,000 = Rs 39,60,000
GST on the construction component (taxable value is the consideration less the one-third deemed land value):
Taxable value = 39,60,000 × 2/3 = Rs 26,40,000; at 7.5% = Rs 1,98,000
Stamp duty and registration on Rs 39,60,000 — confirm the rate and cess for your ward.
Before duty, the real cost is already Rs 41,58,000, not Rs 39,60,000
That is about Rs 2,31,000 per sq m all-in, against the Rs 2,20,000 quoted.
What else is added on top of the rate?
Two things, usually. GST applies to a purchase of an under-construction flat, so ask for the rate applicable to your case in writing. Then stamp duty and registration, because this portion is a purchase for consideration like any other flat purchase. In Mumbai municipal limits stamp duty is 6% for a male buyer and 5% for a female buyer, including the 1% metro cess, with registration at 1% capped at Rs 30,000 above Rs 30 lakh.
Does the Rs 100 stamp duty concession help here?
No. The Rs 100 concession on the PAAA covers your rehabilitation flat only, not extra area bought for money. Get the rate, the area basis and the all-inclusive total in writing before signing, and have your chartered accountant confirm the tax position for your own facts.
Work it out for your own society
Convert between carpet and built-up area in seconds, so you can check exactly what basis the builder's rate is being applied to.
Open the Carpet to Built-up Area ConverterCommon questions
Should the builder quote the extra area rate on carpet or built-up area?
Insist on RERA carpet area. Carpet area is the net usable floor area, excluding external walls, shafts and the exclusive balcony or open terrace, but including internal partition walls. The sale agreement must state carpet area. A rate applied to built-up area means you pay for square feet you cannot use, which is the commonest overcharge members face.
Do I pay stamp duty on the extra area I buy?
Yes. Extra area is a purchase for consideration, so ordinary stamp duty applies. Within Mumbai municipal limits that is 6% for a male buyer and 5% for a female buyer, including the 1% metro cess, plus a registration fee of 1% capped at Rs 30,000 where the value exceeds Rs 30 lakh.
Does the Rs 100 PAAA stamp duty concession apply to extra area?
No. Once the Development Agreement is fully stamped, the Permanent Alternate Accommodation Agreement cannot be charged beyond Rs 100 under Section 4(1) of the Maharashtra Stamp Act 1958. That concession covers your rehabilitation flat only. Any additional area bought for consideration is treated as a normal purchase and is stamped accordingly.
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