Know All About FSI or FAR in Chennai 2025

FSI (floor space index), also known as FAR (floor area ratio), is a widely used technical term in the real estate industry to determine the maximum floor space that can be built on a piece of land. In other words, it is the proportion of a building’s total completed floor space to its entire land area. This can be an important metric for both developers and home buyers. For developers, FSI will help them determine how much they can build on any given plot of land. Home buyers should also keep in mind that there are zones with higher FSI than others – such as those near train stations or business districts.

Everything About FSI or FAR In Chennai

In 2019, the Tamil Nadu government published the new Development and Building Rules applicable to the entire state. These rules divide buildings into two types: high-rise and low-rise. Non-high-rise buildings are those that have a height of less than 18.30 metres. The maximum Floor Space Index allowed for these non-high-rise buildings is 2. However, certain exceptions apply when calculating this metric.

Understanding FAR and Its Calculation 

The FSI is calculated by dividing the total covered area (plinth) on all levels, excluding those exempted by these regulations (as mentioned above), by the plot area, which includes a portion of the site used as an exclusive passage.

FSI or FAR = Total covered area on all floors / Total plot area 

With an FSI of 2, the total plinth area that can be built is twice the plot size. For instance, if the plot area is 2400 square feet, the total plinth area of all levels that can be built in that plot is up to 4800 square feet.

FSI in Chennai for Residential and Commercial Buildings

Find below the FSI for residential and commercial buildings in Chennai.

FSI for Residential Buildings in Chennai

Floor space index for residential buildings in Chennai is different for spaces located in different zones and areas. As per the database maintained by CMDA (Chennai Metropolitan Development Authority), the FSI in Chennai for residential spaces ranges between 1.5 to 2.0 for most locations. However, it is subject to change as per the rules and regulations released by the local government. 

FSI for Commercial Buildings in Chennai

FSI for commercial spaces is usually higher than that of residential buildings. As per CMDA rules and regulations, the FSI in Chennai for commercial buildings ranges between 2.0 and 3.0. It is subject to change as per the rules and regulations released by the local government. 

Guidelines for the Premium FSI in Chennai

Premium FSI is an extra FSI given in addition to the permitted FSI. The Premium FSI will be permitted in the Chennai Metropolitan Area, with the exception of the Redhills catchment area, which is zoned for development, and the area of water bodies maintained for drinking water purposes by the Chennai Metropolitan Water Supply and Sewerage Board. The Premium FSI will be approved if the following road width conditions are met:

The developer, however, will receive an additional benefit in the form of Premium FSI in case of proper land extension. For example, if the regularly permitted FSI is 1.50, the proportionate land required is 2/3 or 0.66 sqm. Every 1 sqm of additional floor area will be developed using Premium FSI. Likewise, if the regularly permitted FSI is 2.0, the proportionate land required will be 1/2 or 0.50 sqm and for FSI 2.5, the proportionate land required will be 2/5 or 0.40 sqm. 

Advantages of FSI and FAR Rules in Chennai

Find below a few major advantages of implementing FSI and FAR rules in Chennai.

• The average FSI value of a project indicates that it is in the development stage.

• FSI rules help maintain a balance between development and sustained growth.

• FSI rules help maintain the skyline of the city.

• The ratio between the open space of the city and the building is maintained.

FSI in Chennai Exemptions

As per the revised norms, the following factors are not considered in the FSI and plot coverage calculations: 

1. Areas covered by stair-case rooms and elevator rooms, as well as corridors, architectural elements, elevated tanks (given the height below the tank from the floor is not more than 1.5 metres), and WC on the terrace above the topmost storey (with a floor area not greater than 10 sqm).

2. Staircases and lift rooms, as well as pathways to them, in the stilt parking floor or upper parking floors.

3. Staircases and lift rooms, as well as passages to and from them, in the basement level or parking floors.

4. Parking area in the basement or on the upper floors.

5. The portion of the stilt parking floor that is open on all sides and is used for parking in cases where parking is planned on an upper floor or floors above a stilt parking floor, subject that the area is not more than 3.0m

6.  Watchman cabins or servant rooms either on the ground floor or stilt parking floor.

7. Service floor with a height of not more than 1.5 metres.

8. A gym room of 150 sqm in floor area.

9. Ground floor or stilt parking floor caretaker cabin or room.

10. Air conditioning plant room and lumber room either in the basement or ground floor.

11. Generator room either in the basement, stilt or ground floor.

12. Electrical /switchgear rooms or AHU (air handling unit) on all the floors.

13. Pump room and meter room either on the slit parking floor or ground floor. 

14. Area dedicated to fire escape stairs and cantilever fire escape passages

15. Area occupied by garbage shaft, service ducts, porch, and portico.

16. Area within the building dedicated to housing machinery for a water treatment plant or a sewage treatment plant has been planned, with proper approval from the Tamil Nadu Pollution Control Board (TNPCB). 

17. Balcony or service utility equal to 5% of each unit or flat in residential buildings and 5% of room area in other structures like hotels and lodges.

18. The area equivalent to a single room meant for letterboxes in residential or commercial multi-storeyed buildings or any group developments.

Cost of the Premium FSI in Chennai

The amount payable by the applicant for Premium FSI (called as Premium FSI Charge) is equivalent to the price of the proportionate land stated above, as determined by the Registration Department’s Guideline Value. Moreover, before receiving planning authorization, the applicant must pay the Premium FSI Charge in one single payment to the Chennai Metropolitan Development Authority (CDMA). 

The applicant will have complete control over the property in order to develop the site. However, retaining an undivided part of land will not qualify you for a Premium FSI. The applicant must express his/her willingness to use the premium FSI at the time of filing his/her planning permission application and give an assurance to pay the Premium FSI charge at the above-mentioned rates before receiving planning permission.

The Bottom Line on FSI in Chennai

We hope the post helps you learn everything about FAR or FSI in Chennai. No official annoucements have been releases in regards with FSI in Chennai in 2024 or 2025. However, it is expected to go high for commercial buildings in certain reas of the city. The proposal for raising FSI in Chennai for commercial buildings to 6.5 has already been submitted to the government.