Mumbai Home & Property Calculators 2025–26

MCGM's capital value formula — and what it does to a terrace or loft

MCGM's own RTI manual sets out its capital value (CV) formula for a built flat as: CV = Base Value (from the Stamp Duty Ready Reckoner) × User Category weightage × Nature/Type of Building weightage × Age Factor weightage × Floor Factor weightage (for RCC buildings with a lift) × Carpet Area. For open land, the formula instead multiplies Base Value × User Category × permissible FSI × Area of Land.

• ·An open terrace in exclusive possession of a flat: valued at 20% of the flat's base-value rate if residential, 50% if non-residential.
• ·A mezzanine floor: valued at 70% of the base rate of the flat beneath it.
• ·A loft or attic floor: valued at 50% of the base rate.

MCGM's manual states the formula's structure and the Ready Reckoner as its base-value source, but does not itself state the final tax-rate percentage applied to the computed capital value — that is a separate general tax rate MCGM applies afterward, so this article does not quote a Mumbai property-tax percentage.

MahaRERA's delay-interest rule

Maharashtra's own gazetted RERA Rules, Rule 18, set the interest a promoter owes an allottee for possession delay — and an allottee owes a promoter for a payment default — at the State Bank of India's highest Marginal Cost of Lending Rate (MCLR) plus two percentage points, replaced by whatever benchmark lending rate SBI fixes if it stops publishing an MCLR. This is the identical formula independently confirmed in Karnataka's and Telangana's own state rules — a common structure across at least these three states, though Maharashtra's own text is the only valid citation for a Mumbai project specifically.

GST on an under-construction flat anywhere in the MMR

CBIC's affordable-housing definition names "Mumbai (whole MMR)" — not just the city proper — as a single metropolitan-city block for GST: a new-construction unit qualifies for the 1% effective rate (no input tax credit) only if its carpet area is up to 60 sq m and its value is up to ₹45 lakh, whether it sits in South Mumbai, Thane or Navi Mumbai. Above either threshold, the standard 5% effective rate applies, also without ITC, per the underlying rate notification. A 55 sq m Thane flat booked at ₹42,00,000 clears both caps at 1% GST = ₹42,000; the same unit at ₹50,00,000 fails the value cap alone and moves to 5% = ₹2,50,000.

What it actually costs to run a Mumbai flat: Tata Power-D's own tariff

Property purchase cost is only part of owning a Mumbai flat — running cost matters too, and it is set locally. MERC's Final MYT Order for Tata Power-D's Mumbai licence area sets the residential (LT I(B)) tariff for FY2025-26 at ₹2.00/kWh energy charge for the first 100 units, ₹5.20/kWh for the next 200, ₹10.79/kWh from 301-500 units, and ₹11.79/kWh above 500 units — each slab also carries a ₹2.76/kWh wheeling charge plus a fixed monthly charge that rises from ₹90 to ₹160 across the slabs.

This is Tata Power's own Mumbai distribution-licence tariff only — it does not apply to BEST, MSEDCL or Adani Electricity areas elsewhere in Maharashtra, each of which has its own MERC-approved tariff order, so do not generalise this figure as "Mumbai's" electricity price without checking which discom actually serves a given building.