FSI (Floor Space Index)
Ratio of total permissible built-up area to plot area, set by local authorities to control building density.
FSI (also called FAR - Floor Area Ratio) determines maximum construction allowed on a plot. Formula: FSI = Total Built-up Area / Plot Area.
How it works
- FSI 1.5 on 2000 sq ft plot = 3000 sq ft total construction allowed
- Higher FSI allows taller buildings or more floors
- Expressed as ratio (1.5) or percentage (150%)
Factors affecting FSI
- Road width (wider roads = higher FSI)
- Location (city center vs suburbs)
- Zoning (residential vs commercial)
- Premium FSI purchasable in some cities
Importance for buyers
- Determines project density (higher FSI = more crowded)
- Affects future value (redevelopment potential)
- Check approved FSI vs actual construction on RERA site
UP Specifics: UP building bylaws set FSI based on development authority rules (LDA, NOIDA, etc.).
Examples
FSI 2.0 allows double the plot area in construction (e.g., 4 floors on ground coverage)
Road >12m width often gets FSI 1.75-2.25 in urban UP areas