Carpet, built-up, saleable — price on the right number
Since RERA, builders must state carpet area, but older agreements and brokers still quote built-up or saleable figures that are 25–40% larger. Interiors are priced on carpet area, because that is the floor you actually furnish.
| Term | What it includes | Typical relationship | Use it for |
|---|---|---|---|
| RERA carpet area | Net usable floor inside walls, plus balcony separately | Baseline | Interior pricing, always |
| Built-up area | Carpet plus wall thickness and balcony | Carpet + 10–15% | Nothing useful to you |
| Saleable or super built-up | Built-up plus a share of lobbies, lifts, amenities | Carpet + 25–40% | Comparing purchase prices only |
A '1,000 sq ft' Mumbai flat advertised on saleable area is commonly 620–750 sq ft of carpet. Quotes based on the larger figure look cheaper per sq ft and cost the same in total.
Three kinds of Mumbai flat
| Stock type | Where | Heights and areas | What we check first | Rate ₹/sq ft carpet |
|---|---|---|---|---|
| Older society stock, 1970s–90s | Bandra, Dadar, Matunga, Chembur, Andheri | Generous heights, small rooms, no shear walls | Wiring age, plumbing material, slab seepage | ₹2,070 – 4,140 |
| Redevelopment rehab flats | Ghatkopar, Vile Parle, Goregaon, Malad | 2,750–2,900 mm, compact, shear-wall | Electrical load, window quality, damp in external walls | ₹1,830 – 3,160 |
| New towers, post-2010 | Powai, Thane, Wadala, Navi Mumbai, BKC | 2,900–3,150 mm, shear-wall, decent handover | Handover spec, what is worth keeping | ₹1,760 – 3,650 |
Excluding 18% GST. Rates are per sq ft of RERA carpet area for a full interior including joinery, ceiling, electrical augmentation, kitchen and painting.
Design and build under one accountable roof
What each stock type actually needs
- Older society stock. Beautiful heights and terrible services. We survey the wiring before quoting: aluminium conductors, rewireable fuses and a 5 kW sanctioned load are common in pre-1990 Bandra and Dadar buildings, and a modern flat with ACs and an induction hob will trip it. Rewiring a 2BHK runs ₹1.4–₹2.6 lakh and is not optional.
- Redevelopment rehab flats. Built to a compliance minimum, handed over quickly. The recurring issues are an under-provisioned distribution board, thin aluminium windows that leak in a westerly monsoon, and external walls that carry damp. We specify BWP for all external-wall joinery here as standard, not as an upgrade.
- New towers. Usually the cleanest start. The work is deciding what to keep — the flooring and bathroom fittings are typically serviceable — and augmenting a socket count that was set by a cost engineer rather than by anyone who lives with devices.
Tell me the year the building went up and I can tell you eighty per cent of what your interior budget is really going to be spent on.
Greenbox principal designer
Suburb price bands for a full flat
| Area | 2BHK, 600–750 sq ft carpet | 3BHK, 950–1,200 sq ft carpet | Note |
|---|---|---|---|
| Bandra West, Juhu, Worli | ₹18.5 – 31.5 L | ₹29 – 51 L | Lane access and salt-air spec add cost |
| Andheri West, Goregaon, Malad | ₹12 – 22 L | ₹20.5 – 35.5 L | The Mumbai median; storage-led briefs |
| Powai, Chandivali, Ghatkopar | ₹13.5 – 23 L | ₹22 – 37.5 L | Good heights, strict society rules |
| Chembur, Wadala, Dadar | ₹13 – 23 L | ₹20.5 – 36.5 L | Mixed old and new stock |
| Thane, Ghodbunder | ₹11 – 18.5 L | ₹18.5 – 30.5 L | Larger layouts, better value per sq ft |
| Navi Mumbai — Vashi, Nerul, Kharghar | ₹10.5 – 17.5 L | ₹17 – 29 L | Easiest logistics in the MMR |
Excluding 18% GST and civil work. Includes joinery, modular kitchen, peripheral false ceiling, electrical augmentation, painting and installation. The bands are built from flats we have completed and invoiced across these suburbs, held at October 2026.
The two weeks Mumbai adds to every project
A flat in Pune and a flat in Powai with identical scope do not finish on the same day. The gap is administrative and logistical, and it is entirely predictable.
- NOC and deposit — three to ten days depending on when the managing committee next meets. We file at design sign-off rather than at mobilisation.
- Permitted hours — 10am to 6pm weekdays and Saturdays in most buildings, no Sundays or public holidays. That is roughly 38 productive hours against 60.
- Service lift slots — material movement often confined to a morning window and shared with other flats.
- Debris days — most societies nominate two days a week. Work that generates debris is scheduled to land before them.
- Monsoon holds — bathroom demolition, external-wall work and waterproofing are scheduled outside mid-June to late September.
Rehab flat, and they told us up front the DB had to be upgraded before anything else. Our neighbour skipped that and trips every time the second AC starts.
Old building, 1982. They surveyed the wiring first and quoted the rewiring honestly rather than discovering it in week six.
Kept the builder flooring and bathroom fittings on their advice and put the money into the kitchen and lighting. Absolutely the right call.
Balconies, grilles and the façade rule
One category of work causes more society disputes in Mumbai than any other: anything visible from outside the building. Committees are consistent about it and owners are consistently surprised.
- Balcony glazing is a façade change in most societies, whatever the neighbours have already done. Some buildings permit it to a standard specification; some prohibit it outright and have made owners remove it.
- Grilles must usually match the building standard in profile and colour. A black powder-coated grille in a building of white ones will be objected to.
- Split AC outdoor units go in designated positions only. Mounting one on a front elevation is the fastest way to a notice.
- External wall chasing for AC piping or wiring needs permission and is best avoided in the monsoon regardless.
- Window replacement is permitted in many societies only if the external appearance is unchanged — which usually means matching the frame colour and division.
- Get it in writing. A verbal yes from one committee member does not survive a change of committee, and the removal cost falls on the flat owner.
The apartment fundamentals
For handover audits, shear-wall constraints, room-by-room scope and phasing that works in any Indian apartment, see our flat interior design services overview.
Selected work by Greenbox Design Studio. Tap any image to enlarge.
Frequently asked questions
How much do flat interiors cost in Mumbai?+
₹1,760–₹4,140 per sq ft of RERA carpet area. A 600–750 sq ft 2BHK runs ₹10.5–₹18.5 lakh in Navi Mumbai and Thane and ₹18.5–₹31.5 lakh in Bandra, Juhu or Worli. A 950–1,200 sq ft 3BHK runs ₹17–₹51 lakh across the same spread, all excluding 18% GST.
Should I price interiors on carpet or saleable area?+
Carpet area, always. A flat advertised as 1,000 sq ft saleable is commonly 620–750 sq ft of RERA carpet. A quote priced on the saleable figure shows a lower rate per sq ft for exactly the same total cost, which is a presentation trick rather than a saving.
Does an older Mumbai building need rewiring before interiors?+
Frequently, yes. Pre-1990 stock in Bandra, Dadar, Matunga and older Andheri buildings often has aluminium conductors, rewireable fuses and a sanctioned load around 5 kW that will not carry modern appliances. Rewiring a 2BHK costs ₹1.4–₹2.6 lakh and we survey for it before quoting rather than after.
What is different about a redevelopment rehab flat?+
They are built to a compliance minimum: under-provisioned distribution boards, thin aluminium windows that admit water in a westerly monsoon, and external walls that carry damp. We specify BWP plywood for all external-wall joinery in these flats as standard and check the electrical load before designing the kitchen.
How much longer does a Mumbai flat project take?+
About two weeks more than the same scope elsewhere. Roughly three to ten days for the society NOC and deposit, then a permitted working week of about 38 hours instead of 60 because of 10am–6pm restrictions and no Sunday work, plus booked lift slots and designated debris days.