What is Floor Space Index & How to Calculate it

What is the meaning of Floor Space Index ( FSI ) ?

FSI stands for ‘Floor Space Index’ also known as ‘Floor Area Ratio’. Floor Space Index means the ratio between the area of a covered floor to the area of that plot on which a building stands. This numeric value indicates the total amount of area on all floors you can build upon a plot.

FSI Formula

How to Calculate Floor Space Index for Building

Floor Space Index is regulated by Directorate of Town and Country Planning Department. They will regulate the FSI value based on the zone of city, type of building and other amenities. Construction companies or builders can only build up to the FSI imposed by the government.

floor space index (fsi)

Assume you have a land of 3000 sq.ft 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. Whether you want to construct ordinary building (up to 2 floors), Special building (more than 2 floors not exceeding 4 floors) or multi-storied building exceeding 4 floors.

Based on your building type, find out your zone FSI which you can find on your State Government’s official website. Generally, different buildings have different Floor Space Index regardless of the location. For the same location FSI can vary for ordinary building and special buildings.

Let us assume that the zone in which you desire to construct the building has FSI of 1.5 for special buildings, now you can build 4500 sq.ft [3000 sq.ft * 1.5] covered area on your land. You can be either option for 2 floors of 2250 sq.ft or 3 floors of 1500 sq.ft without affecting other municipal rules.

You should also note that you have to follow other municipal rules such as minimum plot extent area, front-back-side and rear setback, OSR (Open Space Ratio) and parking space etc.

What is Premium FSI

Regardless of zone location and building type, there are some allowable deviations. If you need to extend the allowable floor space index you have to pay a premium fee to the government. To avail this FSI the abutting road of the land must be at least 30 feet wide.

  • 30 to 40 feet road width 20% premium FSI
  • 40 to 60 feet road width 30% premium FSI
  • more than 60 feet road width 40 % premium FSI can be availed.

If the land location of the building has 30-40 feet of abutting roadway then you can avail the premium FSI of 20%, which means you can build 20% more than allowable Floor Space Index

For example, If you have 2000 square foot land located near 30 feet road where normal FSI is 1.5 then you can make avail of the premium FSI 20% by paying the premium fee.

Leave a Reply