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What Is FSI | What Is FAR | What Is Premium FSI | FSI Full Form | FAR Full Form

FSI Vs Far

What Is FSI?

FSI Full-Form Floor Space Index

FSI (Floor Space Index) means Floor space index- the ratio of the built-up space on a plot into the Area of the plot is a regulation followed at the development control norms of many cities.


FSI directly tells us about the maximum permissible floor area, which may be built on a plot.

Numerically, FSI (Floor Space Index) is the ratio of building floor covered Area into the raw Area available on that plot/land. The floor space index value is changed from place to place. It also depends upon the type of building.

The FSI ratio value of a specific area is easily found in all the building bylaws for various cities and municipalities. Different cities or municipalities could have different bylaws and, consequently, different values.

The Formula for the Floor Space Index (FSI) Is

• Floor Space Index = Floor Space Covered in all Floors / Area of the Plot

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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.

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

Multi-storeyed Building – Exceeding 4 floors

Special Building – more than 2 floors not exceeding 4 floors,

Ordinary Building – Up to 2 floors less than 4 flats/dwelling units,

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.

Let say your zone FSI is 1.5 for special buildings.

Now you can build (3000*1.5 ) 4500 ft2 covered Area on your land.

It can be either 2 floors of 2250 ft2 or 3 floors of 1500 ft2 without affecting other municipal rules.

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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.

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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 wallsbasic 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.

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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.

• 30 – 40 Ft Road Width – 20 % Premium Floor Space Index

• 40 – 60 Ft Road Width – 30 % Premium Floor Space Index

• 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

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