FSI/FAR are commonly used in the real estate. It is the ratio between the total built-up area and the total plot area. It is allowed by the government for a particular locality. It primarily describes the ratio of the total covered area of construction to the total plot size. It is also termed floor space ratio (FSR), floor area ratio (FAR), site ratio (SR) or plot ratio (PR).

FSI norms are normally based on the National Building Code

Buildings with different numbers of stories may have equal FAR values. Every city has a limited capacity or limited space that can be used safely. Any use exceeding this limit sets unnecessary pressure on a city.

FSI/FAR value may be amended from time to time depending on the development/growth of city, which improved land value, based on power, water, and sewer facilities.

FAR is differ because:

1. Population dynamics

2. Growth models

3. Construction exercises

4. Nature of the land or space where a building is located.

Industrial, residential, commercial, agricultural and non-agricultural spaces have different safe loading factors, so they normally have different FARs.

FAR is an essential deciding factor for development in any nation or city. A low FAR is a common barrier to construction. Many industries, mainly the real estate industry, want hikes in FAR to more utilise space and land resources to developers. A raised FAR permits a developer to complete more building projects, which necessarily points to higher sales, decreased expenditures per project and extensive supply to match demand.

FSI regulates by the Directorate of Town and Country Planning (DTCP) department. Of concerning city The floor area ratio (FAR) can be applied in a plan to restrict urban density. While it directly restricts building density, indirectly it also restricts the number of people that a building can include, without managing a building’s outer shape.

FAR is the ratio of the combined gross floor area of all total covered area on all floors to the gross area of the plot.

Floor Space Index (FSI) = Total covered area on all floors / Gross Plot area

4.1 Permissible F.A.R  Means the basic F.A.R permitted by the Competent Authority as a matter of right.

Permissible FSI/FAR value depends on:

• Size of the plot

• Type of building (residential, commercial, institutional, worship, etc.)

• The width of the adjacent road

• Availability of power, water, sewer lines

4.2  Base F.A.R Means the base F.A.R permitted in a Base Zone by the Competent Authority as a matter of right.

4.3 Chargeable/Premium F.A.R/FSI Means the F.A.R available by payment Premium/Chargeable FSI, if you need to extend the allowable Floor Space Index, you have to pay a premium fee to the government. To get this FSI, the adjacent road of the land must be 30 feet.

• 30 to 40 Ft Road Width – 20 % Premium FSI

• 40 to 60 Ft Road Width – 30 % Premium FSI

• More than 60 Ft Road Width – 40 % Premium FSI

If the land location of the building has 30 – 40 feet adjoining roadway, then you can avail the premium FSI of 20% which means you can build 20% more than allowable FSI.

Benefit of the Floor Space Index (FSI)

The FSI may be regarded as a limitation but it has its own benefits in a city or a place where construction is progressing at a tremendous speed.

• It manages the ratio of open space to developed space.

• It manages the shape of the city.

• An average FSI value ensures a stable development of the project.

• Managing the balance between supported, planned growth and development is necessary.

Application of FAR

For example, if the FSI/FAR is 2 and the total plot area is 1,000 sq.ft., then the maximum buildable area of the building must not be more than 2,000 sq.ft.  FAR does not have limitations on how many floors a building must have, except for the height and other limitations the municipal or development body holds in specific areas and zones. Therefore, one can construct a building with only two floors extending 2000 sq.ft. or four floors with 500 sq.ft. each.. Public amenities such as common area, parking area, interior open space, pipes and basement completely used for parking are excluded while calculating FSI.