Floor Space Index (FSI) and Its Impact on Urban Development

How to Calculate Fsi for Building?

FSI regulates by the DTCP ( Directorate of Town and Country Planning) department.

They will regulate the FSI (Floor Space Index) value based on city zone, type of building, and other amenities. Construction companies or builders can only build-up to the FSI imposed by the government.

FSI × Plot Area = Built-up Area

What Is Fsi in Construction?

FSI Example Calculation

To explain the Floor Space Index (FSI), Assume you have a land of 3000 ft² and you want to construct a building on that land.

The first thing, you need to know is what type of building you are planning to construct?

1. Multi-storeyed Building – Exceeding 4 floors
2. Special Building – more than 2 floors not exceeding 4 floors,
3. Ordinary Building – Up to 2 floors less than 4 flats/dwelling units,
4. There are other types of buildings also exist. (Industrial Building, Group housing, etc.).

For the sake of this example, we stick to these types. Based on your building type, find out your zone Floor Space Index (FSI), which you may find on your state govt’s official website.

Generally, different buildings have different FSI (Floor Space Index) regardless of the location. For the same location, FSI (Floor Space Index) can vary for ordinary buildings and special buildings.

1. Let say your zone FSI is 1.5 for special buildings.
2. Now you can build (3000*1.5 ) 4500 ft2 covered Area on your land.
3. It can be either 2 floors of 2250 ft2 or 3 floors of 1500 ft2 without affecting other municipal rules.

What Is FAR?

FAR Full-Form Floor Area Ratio

The floor area ratio is the relationship between this total amount of usable floor area that a building has, or has been permitted to have and this total area of the lot where the building stands.

The ratio is determined by dividing the gross or total floor area of the building by the gross area of the lot. A higher ratio is more likely to indicate a dense or urban construction. Local governments use FAR (Floor Area Ratio) for zoning codes.

The Formula for the FAR (Floor Area Ratio) Is

Floor Area Ratio = Total Building Floor Area x 100 / Gross Lot Area

How to Calculate the Floor Area Ratio?

The FAR (Floor Aea Ratio) is calculated by dividing the total building floor area by the gross lot area.

What Is Far in Construction?

FAR Example Calculation

FAR (Floor Area Ratio) is calculated by a simple formula –

A total covered area of all floors divided by this plot area. Suppose the builder has got a plot of 1,500 m², and the permissible FAR (Floor Area Ratio), according to development plans, is 1.5.

He is allowed to construct a building on 3,000 m2 of this plot. It is the ratio of this total floor area in the building compared with the total plot area.

The constructed Area would include the walls, basic structure, lobby space, or staircase. FAR (Floor Area Ratio) can be different inmunicipality, various cities, locality, or even depending upon the nature of land- industrial, commercial, residential, agricultural, or non-agricultural.

This is because of the organic growth pattern, population dynamics, and construction activities varies from city to city. Much depends on governmental regulations.

What Is Premium FSI?

Premium FSI (Floor Space Index) If you need to extend the allowable FSI (Floor Space Index), you have to pay a premium fee to the govt. To avail of this FSI (Floor Space Index), the abutting road of the land must be at least 30 feet.

1. 30 – 40 Ft Road Width – 20 % Premium Floor Space Index
2. 40 – 60 Ft Road Width – 30 % Premium Floor Space Index
3. More than 60 Ft Road Width – 40 % Premium Floor Space Index

If the land location of the building has 30 – 40 ft abutting roadway, then you can make avail the premium FSI (Floor Space Index) of 20%, which means you can build 20% more than allowable FSI.

For Example,

If you have 2000 ft² Land located near 30 ft road (where normal FSI is 1.5), then you can make avail of the premium FSI (Floor Space Index), 20% by paying the premium fee. So,

Built-up area = 2000 x Normal FSI x Premium FSI %

Built-up area = 2000 x 1.5 x 20%

Built-up area = 3600 Sq.ft

FAQs on Floor Space Index (FSI)

What is the full form of FSI?

FSI stands for Floor Space Index.

What does Floor Space Index (FSI) mean?

FSI refers to the ratio of the built-up space on a plot to the area of the plot. It is a regulation used in development control norms of many cities.

How is FSI calculated?

FSI is calculated using the formula: Floor Space Index=Floor Space Covered in all FloorsArea of the Plot\text{Floor Space Index} = \frac{\text{Floor Space Covered in all Floors}}{\text{Area of the Plot}}Floor Space Index=Area of the PlotFloor Space Covered in all Floors​

Who regulates FSI?

FSI is regulated by the Directorate of Town and Country Planning (DTCP) department. The FSI value is determined based on the city zone, type of building, and other amenities.

Can the FSI value vary?

Yes, the FSI value can vary from place to place and depends on the type of building and location. Different cities and municipalities have different bylaws and consequently different FSI values.

How do you calculate the permissible built-up area using FSI?

The permissible built-up area can be calculated using the formula: $\text{Built-up Area}=\text{FSI}\times \text{Plot Area}$

What is an example calculation of FSI?

For example, if you have a land area of 3000 sq. ft. and the FSI for special buildings in your zone is 1.5, you can build up to: $3000\times 1.5=4500\text{ sq. ft.}$ This can be distributed over multiple floors as long as the total built-up area does not exceed 4500 sq. ft.

What is FAR?

FAR stands for Floor Area Ratio. It is the relationship between the total usable floor area of a building and the total area of the lot where the building stands.

How is FAR calculated?

FAR is calculated using the formula: Floor Area Ratio=Total Building Floor Area×100Gross Lot Area\text{Floor Area Ratio} = \frac{\text{Total Building Floor Area} \times 100}{\text{Gross Lot Area}}Floor Area Ratio=Gross Lot AreaTotal Building Floor Area×100​

What is premium FSI?

Premium FSI allows for an extension of the allowable FSI by paying a premium fee to the government. The amount of premium FSI depends on the width of the road abutting the land.

How is premium FSI calculated?

If the land is near a road with a width of 30-40 ft, a 20% premium FSI can be availed. For example, if the normal FSI is 1.5 and the land area is 2000 sq. ft., the built-up area using premium FSI is: $\text{Built-up area}=2000\times 1.5\times 1.2=3600\text{ sq. ft.}$