What is Floor Space Index
- Real Estate

What is Floor Space Index?


What is FSI’s full form? The Floor Space Index is the total area covered by all floors divided by the total plot area on which the building is built. The area covered by floors of buildings is known as the built-up area.

In some areas, the floor space index is also called the floor area ratio. This article will tell you about the floor space index, its components, key parameters, and its importance. If you want to get a clear understanding of FSI, you should read the whole post.

Overview of floor space index(FSI)

TheFSI meaning is the total area of floors divided by the total area of the plot. In simple terms, it is a ratio that helps you decide how much construction should be done on the plot.

The FSI values are based on amenities, location, and type of building. The complete structure of the plot is based on several parameters, including the plot size, location, and building use.

What is premium FSI?

The premium FSI is applied if there is a broad road associated with the plot. The different premium FSI is applicable based on road width. The minimum width isconsidered 30 feet.

After taking the different cases of the width of the road, the premium FSI are applied as follows as

  • If the road width is around 30 to 40 feet, the builder can get 20% more FSI.
  • If the road width is around 40-60 feet, then the builder can get 30% more FSI.
  • If the road width is more than 60 feet, then the builder can get an FSI of more than 40%

The 20% FSI means that 20% of construction takes place over the exact permissible limit.

Factors on which the FSI depends

Here is the list of factors on which the floor space index depends.

1. Plot locality

The urban areas, usually near the city have a higher FSI than the distant localities and suburban localities beyond the city limits. The scarcity of open land in the cityis the major reason for the high FSI in these areas.

2. Building use

Plots that are used for commercial purposes have a greater FSI than the plots constructed for residential purposes. For example, in Mumbai, the FSI maximum is 3.0 permits for residential projects, 5.0 for commercially constructed projects, and 4.0 permits for mass housing projects.

3. Plot size

The FSI is higher in larger plots than in smaller areas. This is important to promote vertical development in deficient land cities.

4. Road width

Some regions have fixed FSI based on the width of the road where the plot is located. Therefore, the higher the width, the greater the FSI that will be permissible.


To sum it up, the higher the FSI, the denser the plot of land is. However, the property price is not based on the floor space index ratio. Moreover, the builder can get the premium floor space index ratio if the main road is at least 30 feet wide.

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