Must Knows

What is the formula for Floor Area Ratio (FAR): All about Floor Space Index (FSI)

[] The Floor Area Ratio (FAR) of a project is an important indicator of the density of the project and how much a home there would cost. We explain what exactly the FAR is, how to calculate floor area ratio and its importance for home buyers

Of the many jargons that one would invariably come across in real estate transactions, are FAR and FSI (floor space index). The two terms, which stand for one and the same thing, confuse many buyers, sometimes because of the complexity associated with it. Let us try to understand it in more simple terms and know more about the floor area ratio formula and FSI calculation formula.

You are reading: What is the formula for Floor Area Ratio (FAR): All about Floor Space Index (FSI)

What is FAR or FSI?

Floor area ratio (FAR in real estate) or floor space index (FSI) denote the maximum floor space that can be constructed on a piece of land. FAR in real estate is a ratio between a building’s total constructed floor area and the land area. Going forward in the article, we have mentioned the floor area ratio formula that can be used for calculation purposes.

[] All about GST on flat

What is the formula for floor area ratio? How is Floor Area Ratio calculated?

Floor area ratio is basically the ratio between the total covered area of all floors of a building to the plot area.

For example, if for a particular plot area of 10,000 square metres, an FSI of 1 is allotted, then, a construction of 10,000 square metres would be allowed for the project.

Similarly, if the FSI is 1.5 and you have a land of 1,000 sq ft, then, you can build up to 1,500 sq ft of covered structure. The FAR calculation formula is quite simple:

Plot Area x FSI = Built-up area 

Note: FAR of 1.5 is expressed as FSI of 150%

Note that FSI is applicable on commercial buildings also.

Undertstanding Floor area ratio formula

In real estate, FAR of a project is the ratio between the total covered area of all floors of a building to the plot area i.e. the space covered by all the floors in the building divided by the area of land on which the project is being constructed. The FAR in real estate or the floor space index is decided by municipal corporations or the development authority, according to the Development Control Regulations (DCR) and varies from one city or even locality, to another.


If the size of the plot or land being used for a project is 500 sq ft and the FAR determined for that particular city/locality is 1.5, then, the total floor area that can be constructed will be 750 sq ft (500×1.5) according to far calculation. As the maximum space available on the ground floor will be around 500 sq ft, hence, with the remaining built-up area of 250 sq ft, it is possible to construct just one more floor. Therefore, considering the plot area and the FAR calculation formula applicable in that particular locality, a developer would be permitted to construct a one-storey building.

[] All about property registration laws in India

Floor Area Ratio and Floor Space Index

FSI, meaning Floor Space Index, also known as Floor Area Ratio (FAR), is the ratio of the total built-up area to the total area of the plot. FAR and FSI are used synonymously, the only difference being that while the floor area calculation is expressed as a ratio, the Floor space Index is an index and FSI calculation is expressed in percentage. How to calculate FSI? The municipal council of a particular area is responsible for establishing the FSI limit in a certain range, in order to regulate the amount of construction and the size of the buildings in that area. Since FSI is a measure that combines the height and footprint of a building, regulating it ensures flexibility in the design of the building.

[] All about e stamping

What is premium FSI?

Criteria for premium FSI:

Road width  Premium FSI
30-40 ft 20%
40-60 ft 30%
Over 60 ft 40%

Hence, if you have a road with a width of 30-40 ft, you will be able to build 20 % more than the permissible Floor Space Index, on payment of the required premium FSI charges.

Recently, the Brihanmumbai Municipal Corporation (BMC) allowed a premium payment of 20% land value of ready reckoner rate (RR), for converting an industrial land into commercial or residential use. This can be done at the time of obtaining the commencement certificate (CC). Technicalities aside, what does this premium payment mean? Irrespective of the exact location or even the zone or the building type, a premium FSI will help you extend the permissible FSI. Premium Floor space index is a fee paid to the government for allowing flexibility.

Land area x normal FSI x premium FSI in percentage = Built-up area

The importance of FAR for home buyers

FAR calculation formula is based on the ratio of a building’s total constructed floor area and the land area.

The FAR value is determined by local municipal corporations, to ensure the best possible living conditions for residents in that area, keeping in mind the density of the population, availability of open spaces, environmental impact of the project and preparedness in the eventuality of a natural disaster. Although the methods of computation of the FAR using far calculation formula differ from one city to another, the value generally does not exceed 2.5.

Read also : Tips for making the down payment for a house

So, how to calculate floor area of a building? The more floor area available to a developer, the taller the building can be. Therefore, if you buy a property in such a project, you will most likely live in a denser area with many other residents and will share common amenities and the expenses on electricity, water, clubhouses, swimming pools, elevators, etc.

However, the resale value for a project with low FAR, will most likely be higher than for a property that was in a high-FAR project. This is because a low-FAR project usually means shorter buildings, lesser population density and more open areas around the project.

[] How is RERA carpet area defined?

Why is Floor Area Ratio important for developers?

Floor area ratio that is reached using floor area calculation is a crucial factor for real estate developers. The approval for the building’s height is provided, based on the available FAR in the locality or city. We have heard about plot owners and builders demanding an increase in FAR. Clearly, a high FAR makes way for more saleable space and it will result in more construction in a structure, leading to the growth of high-rises. This way, the demand for housing units will be met while benefitting developers, in terms of increased sales and leases.

Benefits of Floor Area Ratio

Rules and guidelines with respect to FAR helps keep the construction in check and also ensures the structural safety of a building, to some extent. In the absence of FAR/FSI rules, unauthorised constructions will increase. Here are some of the benefits of FAR:

  • There is a clear demarcation between open spaces and built spaces.
  • Helps authorities to foster stable, planned growth

What to know about FAR violation?

An FAR violation by a developer usually comes to light, only when the relevant development authority issues a completion certificate. Therefore, home buyers should ask to see the completion certificate, before buying a property in the project. Buying a property in a project that has violated the FAR regulations of the city/locality, could have serious repercussions on your credit worthiness, if you were to apply for a loan.

Exceptions to Floor Area Ratio

Some important exceptions on how to calculate floor area ratio are amenities like common spaces, parking areas, any interior open space such as the balcony, basements exclusively used for parking, attics, exterior spaces, sports courts, etc. These areas are not included in the FAR.

Floor Area Ratio: Myths and facts

Myth: Properties with high FAR have a low value

This is one of the most popular myths regarding FAR. High FAR value means there would be additional infrastructural costs. However, it has no direct connection with the value of the property.

It is often believed that increasing the Floor Area Ratio can reduce the cost for the builders. However, in such cases, it may usually lead to additional cost, since the authorities charge a premium on the additional FAR or FSI. In cases where the FAR/FSI does not come with such additional charges, the increased FAR/ FSI results in taller building constructions and this could involve increased costs on firefighting, parking, environment clearance, etc.

Myth: Developmental projects are affected in the absence of FAR

Contrary to the popular belief, there is no hindrance or obstruction in the construction of developmental projects where FAR is absent. This is because the developers take into consideration the overall health of the projects before constructing them.

Frequently asked questions about Floor Area Ratio

Will an increase in FAR bring down property cost?

There is a reason why FAR in different areas is fixed or needs to be decided by the authorities. For example, in high-seismic zones, allowing real estate developers to construct high-rises, without any limit, is unsafe. On the other hand, a higher FAR will help the builder to develop more units, thereby, bringing down the cost of development. Nevertheless, the input cost in construction is also a major determinant of what the final price will be. Hence, a mere increase in the FAR, cannot lead to a decrease in property prices.

Do small cities lag behind due to lower FAR?

The FAR depends on the development control regulations (DCR) and it is calculated, keeping in mind the safety of the structure and its surroundings. Tier-2 and tier-3 cities have comparatively lower job opportunities and underdeveloped or developing infrastructure and hence, avenues for growth are lower, which leads them to lag behind. FAR is not the only factor which affects the development of a city.

Floor Area Ratio in Indian cities

Real estate developers often ask for a higher FAR, to bridge the demand-supply gap. Often, unscrupulous builders may even violate FAR regulations. It is very important to follow the rules, so as to provide safe living conditions for everyone. In India, the FAR ranges between 1 and 3.5.

[] Development code pertaining to residential and non-residential premises

FAR in residential premises: Plotted housing

floor area ratio

Source: MoHUA

FAR in group housing

How to calculate floor area ratio in group housing? The number of dwelling units is calculated on the basis of the density pattern given in the development plan, taking into consideration a population of 4.5 persons per dwelling unit. The maximum FAR is 125 or 1.25. Higher FAR may be given, depending on the pattern of development and should not exceed 150.

Latest updates on FAR

Update on March 1, 2022

Maharashtra govt increases FSI for slum rehabilitation projects in the state

In a move that will push housing for all and promote slum-free cities in Maharashtra, the state government has increased the Floor Space Index (FSI) to four times from earlier three for slum rehabilitation projects across the state as per the existing guidelines for Mumbai. For the rest of the state, the government has revised the Unified Development Control Promotion Regulations (UDCPR) to give effect to this increase in the FSI.

Update on November 12, 2021

Redevelopment of housing societies in Ahmedabad to be put on fast track

The redevelopment of old housing societies, which was delayed owing to the COVID-19 pandemic, will now be expedited in Ahmedabad. About 105 housing societies, mostly low rises in the city’s posh western localities, have entered into an agreement or are planning to sign MoUs with developers to rebuild their houses. As per an official of Ahmedabad Municipal Corporation, developers are focusing on these low-rise societies to take advantage of the underutilised Floor Space Index (FSI) of 3.6 and 2.7 to transform the area into 14-storeyed apartment.

Read also : Letter of Credit: All you need to know

Update on Oct 6, 2021

Centre approves coastal zone management plan for Mumbai

The Ministry of Environment, Forest and Climate Change has approved the Coastal Zone Management Plan (CZMP) for Mumbai city and suburbs. The move has opened land parcels along the city’s coastal region, under different CRZ categories for real estate developments. Several housing societies and slums in the city can now go for redevelopment based on the plan, as these areas will get a Floor Space Index (FSI) or permissible development equal to other parts of the city.

UP government hikes FAR

The Uttar Pradesh government allowed amendment of the Greater Noida Industrial Area (Fifth Amendment) Building Regulations, 2021. Hereon, information technology and other such companies will be able to construct double the number of floors than what has been allowed so far, as the FAR allowed for such housing complexes was increased from 1 to 2. Similarly,  non-polluting industrial units will be allowed to construct 4.25 times of space over the size of the plots. While the FAR for 2 will be given to them at the time of the allotment, an additional 2.25 FAR can be bought by paying the required premium. The FAR for new residential group housing, commercial and mixed-use projects will remain the same and capped at 5.25.

MCG’s town planning wing to recover FAR dues

In order to recover losses and add to its revenue, councillors have raised a demand for a town planning wing with the Municipal Corporation of Gurgaon (MCG) that would recover dues on the purchasable FAR. As of now, there is no chief that heads the town planning wing. The MCG has 134 sq kms within its jurisdiction but is able to raise barely Rs 10 crores from purchasable FAR, compounding fees and approval, while a lot of collection remains pending.

Registrations on hold in some NCR regions, due to violation of building codes

In spite of an increase in the FAR for residential plots in colonies, serious violations had been noted in Gurgaon, due to which the Department of Town and Country Planning (DTCP) has sought to halt the registration of properties in such places. The sale and purchase of such properties will, hence, become difficult for such owners. RS Batth, district town planner (enforcement) has directed that registry of residential floors, which have been constructed by violating building rules, after receiving the occupation certificates (OC), should be put on hold in Gurgaon, Wazirabad, Manesar, Badshapur, Kadipur and Garhi Harsaru, till the time property owners restore the buildings as per norms.

Haryana amends Building Code 2017

Chapters 6 and 7 of Haryana building code have been amended and the revised rules are as follows:

Plot size Maximum permissible ground coverage Permissible basement Maximum FAR Maximum height
Up to 60 sq metres 85% single-level 220% 16.5 metres
60-150 sq metres 80% single-level 200% 16.5 metres
150-225 sq metres 70% single-level 180% 16.5 metres

Premium FSI in Karnataka

First mooted in 2017, the Karnataka government gave its sanction to premium FSI in 2020. The permitted FAR carries no fee but those who want premium FAR will have to shell out 50% of the guidance value of the additional area that they will construct using the extra space, according to the draft rules notified by the government. This plan is now open for citizen feedback.

The proposal of the Urban Development Department and planning authorities to introduce premium FAR (Floor Area Ratio) has received an approval from the government. In June 2021, the Karnataka government issued a notification pertaining to the premium FAR, allowing developers and citizens to build additional 0.6 times the existing floor area ratio. The minimum road width for seeking the premium floor area ratio must be nine metres and only in areas that have been identified as ‘impact zones’.

The move will not only bring more revenue to the government but will also boost the vertical growth in the real estate sector.

Delhi’s master plan for 2041

The upcoming Master Plan 2041 for Delhi (MPD), it is hoped, will result in a transformation of the capital. Residential colonies that sprung up over 50 years back may see redevelopment activity picking up. The Delhi Development Authority (DDA) has prepared the MPD 2041 with the National Institute of Urban Affairs (NIUA). DDA vice-chairman Anurag Jain has said that the DDA will extend support wherever needed. Some colonies with single-floor houses will benefit, because previously the FAR was 1.33 but now it is 2. In June 2021, the DDA put the draft MPD -2041 before the public, inviting suggestions and objections within the next 45 days. Delhi Lieutenant Governor, Anil Baijal, has directed constitution of a board of enquiry, to be set up by the DDA, for considering the objections and suggestions of the public on the draft MPD – 2041. The public hearing on the draft (MPD) 2041 has been extended till November 24, 2021.

Maharashtra may ease premium payable on FAR

In an attempt to revive the ailing real estate sector in the financial capital of India, the Maharashtra government may announce a reduction of premiums payable by builders, to avail of buildable area for their projects in Mumbai. Last year, the previous government had lowered the rates from 50% to 40% of the ready reckoner values for a two-year period. This may be further slashed by 10%-15%.

Punjab Local Bodies Department to identify land for affordable housing 

The urban local bodies in Punjab are in the process of identifying land for developing affordable housing. Two categories of units, that is, apartments of 60 sq metres for the economically weaker section (EWS) and 110 sq metres for the middle income group (MIG) may come up. While the cost of the project is yet to be determined, the FAR is 3.50 for projects between one acre and five acres.

UP okays higher FAR for industrial plots

The Uttar Pradesh government has given its nod to mixed-land use for industrial plots. FAR for areas that have already been developed, will be increased to 2.5 with 1.5 as common FAR and one as purchasable FAR. For those areas that are yet to be developed, the FAR will be 3.5 including 2.5 as common FAR and one as purchasable FAR. However, this will differ from place to place.

Noida likely to change data centre building rules

The Noida Authority’s planning department has started the process of revising building regulations, to attract investors planning to set up data centres in the city. The floor height restrictions are expected to be relaxed and additional ground space and floor area ratio would be allowed for building data centres.

In January 2021, the UP government notified its data centre policy. To pass on the incentives proposed by the government to the allottees, industrial development authorities may have to ease the existing building norms. The authority may offer floor area ratio of up to 4 to data centre operators, the maximum FAR allowed for any category. 

DTCP in Gurugram identifies around 1,000 buildings for violating plans

The Department of Town and Country Planning (DTCP) has identified about 1,000 buildings in three blocks of DLF phase 3 in Gurugram, which have violated the plans approved by the authorities. The owners of these structures that have been developed on plots meant for the economically weaker section (EWS), have built additional floors and executed unauthorised constructions even after obtaining the occupancy certificates (OCs). The licences for residential colonies are given as per the provisions of the Haryana Development and Regulation of Urban Areas Act, 1975, and the Haryana Development and Regulation of Urban Areas Rules, 1976. About 15% of the plots in the licenced colonies are reserved for the EWS category.

When approving the zoning plan, it was categorically mentioned that only one dwelling unit was permitted in the EWS category of plots. Also, 66% of ground coverage and 2.64 FAR is permitted, in accordance with the prevailing policy.

FAR: Quick recap

What is included in gross floor area?

This consists of the lobbies, area for tenants and common area, mechanical equipment areas, staircase, basement, laundry, storage rooms, restrooms and atriums.

What is not included in gross floor area?

Exterior spaces, balconies, patios, parking, walkways and driveways that are covered, attics and outdoor sports courts, are not included in the gross floor area.


Is FAR and FSI the same?

Yes, these are used synonymously. FAR is the Floor Area Ratio and FSI stands for Floor Space Index. This ratio is determined by dividing the built-up area of a building with the total size of the plot.

What is 2.5 FSI?

If the FSI is 2.5, this means that a builder with a plot of 1,000 sq metres, can construct 2.5×1,000 sq metres, that is 2,500 sq metres, according to FSI calculation formula.

What is GFA?

GFA refers to Gross Floor Area and is used to calculate FAR. tenant area, meeting rooms, mechanical equipment area, stairwell, lobbies, restrooms, etc., are included in the GFA.

What is a good floor area ratio?

Most developers look for a high FAR. However, a good floor area ratio will also depend on the city and different localities within the city. In metropolitan cities such as Delhi, the FAR ranges from 1.25 to 3.

Does floor area ratio include garage?

The floor area ratio does not include unoccupied spaces like parking, garages, etc.

What is floor area ratio formula?

The Floor Area Ratio (FAR) is calculated as per the formula: Floor Area Ratio (FAR) = Total area of the building / plot size.

(With inputs from Sneha Sharon Mammen and Harini Balasubramanian)

Copyright belongs to:

Category: Must Knows

Debora Berti

Università degli Studi di Firenze, IT

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button