The Floor Space Index (FSI) or Floor Area Ratio (FAR) is a crucial component of the real estate sector in India. FSI meaning can be expressed as the maximum permissible built-up area allowed on a plot of land, expressed as the ratio of the total floor area covered to the available land area. It is typically determined based on guidelines set by the National Building Code and regulated by the municipal or local authorities of the state government.

FSI plays a significant role in determining the attractiveness of a location and its population density, as well as its impact on the environment. High FSI can lead to a reduction in open spaces, which can affect home buyers’ decisions. The National Building Code provides guidelines for building construction activities throughout the country, and FSI is an important consideration in this process.

Simply put, FSI determines the amount of floor space that can be built on a given plot of land. This further reiterates why FSI calculation should be an important part of your home-buying process.

Floor Space Index
Floor Space Index

What is Floor Space Index?

FSI and FAR are two terms that refer to the maximum permissible built-up area allowed on a plot of land. Although both terms are used interchangeably, they are denoted differently with FAR expressed in decimals and FSI expressed in percentages. The FSI can vary from city to city and even from one locality to another within a city. Moreover, the FSI can vary in the same location depending on the number of floors of the building and other amenities.

The FSI is regulated based on the city zone, type of building, and other amenities. Builders are required to furnish details of the proposed building to the respective zone for approval before the construction of any project. These details include whether it is a residential or commercial building, the height and structure of the building, and the area of land that it will be built on.

Several factors directly impact the FSI, with the location being the primary factor. In locations where there is a metro, the FSI is usually higher due to the lack of space. However, FSI could be low in rural areas because of the sheer volume of land available for construction. The size of the plot is also a factor that can impact the FSI. Municipal authorities may calculate higher FSIs for larger plots of land.

Another factor that can impact the FSI is the plot’s proximity to a road. Any plot adjacent to a road will have a higher FSI due to the width of the road. The FSI calculation is made using a simple formula that takes into account the total built-up area and the plot area (explained below).

FSI Formula 

In order to calculate the Floor Space Index (FSI), you need the total floor area of every floor as well as the total area of the plot of land. It can then be calculated by:

FSI = Total Floor Area of all Floors of the Building / Plot area x 100

To calculate the FSI, you will need to determine the total floor area of all floors of the building and the total area of the plot on which the building is constructed. The FSI is calculated by dividing the total floor area of all floors of the building by the plot area and multiplying the result by 100.

Floor Space Index Calculation 

The calculation of FSI is based on the rules and regulations laid down by the local governing authorities, such as the Municipal Corporation, Development Authority, or Town Planning Department. 

To calculate the FSI, the built-up area of all floors is considered, including basements, mezzanines, and other levels. It is important to note that the calculation does not include common areas such as car parks, staircases, lobbies, and elevators.

Let’s consider you have a building with a total floor area of 10,000 square feet and a plot area of 5,000 square feet. To calculate the Floor Space Index, you would use the formula that we have shared above.

So going by the formula, the calculation will be:

FSI = 10,000 sq. ft. / 5,000 sq. ft. x 100

FSI = 200%

In this example, the FSI is 200%, which means that the total floor area of the building is twice the area of the plot on which it stands. This indicates that the building has more than one floor. Yes, the FSI calculation is that simple!

Why is FSI important?

Floor Space Index plays a crucial role in the development of real estate projects in India. It has a direct impact on the density of the area, the size of the building, and the number of floors and occupants it can accommodate. Most importantly, FSI determines the maximum permissible floor area that can be constructed on a plot of land, which in turn affects the economic viability of the project.

FSI also has a significant impact on the infrastructure of the area. The more the FSI, the higher the demand for basic amenities such as water supply, drainage, and electricity. Therefore, local authorities regulate the FSI to ensure that the infrastructure is capable of supporting the additional load.

FSI also affects the overall urban development of the area. A higher FSI results in the construction of taller buildings, which in turn increases the density of the area. This can have a positive or negative impact on the overall aesthetic appeal of the area, depending on how well the buildings are designed and maintained.

Premium FSI

The Premium FSI meaning is a bit different when compared to normal FSI. It is essentially a mechanism that allows developers in India to increase the floor space of a building beyond the standard FSI limit set by the local municipal authority. Premium FSI can be obtained by paying a premium to the government or the local municipal authority. It is usually higher than the standard FSI and varies depending on the location and purpose of the construction project.

The premium FSI system is usually implemented in areas where land is scarce, and the demand for space is high. Builders who pay a premium to the local authority are granted premium FSI which is then used for various development projects in the area.

Width of the road next to the plot

Premium FSI to be levied
30-40 ft.20%
40-60 ft.30%
More than 60 ft40%

FSI values in major cities in Kerala

The FSI values in the state of Kerala, as stipulated by the Kerala Municipal Building Rules, vary in the range of 150% to 300% depending on the type of development, location, and other factors.

It is worth noting that these FSI values are only approximate figures and can vary within a city based on the specific zoning regulations of different areas. These values are subject to change based on the local government policies and the development needs of the city.


Whether you are a first-time homebuyer or a seasoned investor, purchasing property is a major milestone that requires careful consideration. It is important to understand the various factors involved in buying a property, which includes FSI meaning and FSI calculation. Educating yourself about FSI and its calculation can help you make an informed decision and avoid potential risks that may arise from a lack of understanding. By doing so, you can safeguard your investment and ensure a smooth and successful property purchase.

Now that you have a clear understanding of what the Floor Space Index is, make sure you explore some of our luxurious residential projects in Kerala. These projects are sure to elevate your lifestyle to new heights of opulence! 

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