FAR / FSI Calculator

FAR / FSI in Indian Cities — A Working Reference

Floor Area Ratio (FAR) — Floor Space Index (FSI) in Mumbai and Pune — is the multiplier that converts plot area into permitted total floor area. It is the single most important number in any city's building bylaw, but it is rarely the only number that limits a project. Ground coverage, height, and setbacks routinely cut FAR's headroom long before the multiplier itself is exhausted. The calculator above reads all four constraints together; this reference explains how they interact.

From Plot to Floors — A Worked Example

The FSI multiplier looks simple — plot area × FSI = permitted Built-Up Area. The complication is how that BUA gets stacked into floors, because each floor's footprint is itself capped by ground coverage. The diagram below traces a 200 m² Bengaluru residential plot through every step.

The arithmetic: plot 200 m² × FSI 2.25 = 450 m² permitted BUA. Ground coverage 50% caps each floor footprint at 100 m². 450 ÷ 100 ≈ 4.5 floors — meaning four full floors plus a setback fifth-floor terrace block, subject to the 15 m height cap.

Which Constraint Binds First?

FSI is rarely the binding constraint by itself. Ground coverage caps the per-floor footprint; height caps the total stack; setbacks shrink the buildable rectangle within the plot. The diagram below shows three scenarios on the same plot — each governed by a different binding constraint — to make the interaction visible.

Typical patterns: Bengaluru and Hyderabad are usually FAR-bound — the multiplier exhausts before the other constraints. Mumbai is often ground-coverage-bound on small plots — the building footprint hits its cap and the only way to use more FSI is to go taller, which then runs into height limits. Plots near airports, in defence zones, and inside heritage precincts are usually height-bound — even a generous FSI cannot be fully used.

FAR Across Indian Cities

Base residential FAR varies dramatically across India — from ~0.9 in Chandigarh's low-density sectors to 3.0+ in Hyderabad's wide-road plots. The chart below compares the published residential ranges for 12 metros. Read it as the headline figure; the calculator picks the precise value for your inputs.

Practical Notes for Plot Buyers

• Confirm the road width with the master plan, not Google Maps. Setbacks and FAR brackets often shift at 6 m, 9 m, 12 m, 18 m and 24 m.
• Corner plots sometimes get ground-coverage relaxation in BBMP, CMDA, and HMDA. Worth checking before assuming the standard cap.
• Premium FSI / TDR is transactional. The base FAR is your default; anything above it requires a payment, a TDR purchase, or an incentive scheme — talk to a CA before pricing it into the project.
• Heritage, airport, defence, and CRZ overlays trump everything. Always cross-check with the city's heritage list and the AAI height NOC before sizing the project.
• The calculator's output is an envelope, not a design. Setbacks define the buildable rectangle; the architect designs within it.

Cross-References

• FSI/FAR Computation for Indian Architects — the deeper guide
• India Regulatory Atlas — city-wise setback & FSI references
• Bylaw Checker — broader compliance audit
• Approval Roadmap — what comes after FAR sizing

Disclaimer: Bylaws change. The calculator uses published rules as of the most recent revision shown in each city's entry; always confirm with the local authority before committing capital. This page is for informational purposes only and is not a substitute for licensed architectural advice.