what is floor area ratio (FAR)

What is Floor Area ratio


What is Floor area ratio (FAR) is the first question which comes to mind before developing any civil engineering construction project.This is what decides the cost of an apartment or flat or bungalow etc.,

Definition of Floor Area ratio (FAR)

As name suggests FAR is the ratio of two areas

1.One constructed area and

2. Total plot area where the construction happens

Floor area ratio (FAR) = Constructed area / Plot Area

Note : In constructed area all the common spaces like parking, Entrance lobbies, Meter rooms on ground floor, chajjas upto 1200 mm and stilt areas etc

Exclusion is FAR

FAR values changes from place to place. High FAR/FSI means more development area and the end user may get more space. Also, one has to understand, for a highrise building, high FAR or floor space index indicate more area in each floor which leads to more dead load and live loads on the foundation.

The end user should approximately check the floor area index/ratio before buying or investing in any development activity considering strict govt norms. Project completion certificate indicates this information.

FAR/FSI Calculations

Plot area and Gross constructed areas indicated in below sketch.

Floor area ratio calculations
Floor area ratio calculations

Also, note that FAR is also dependent on the width of the road the plot is abutting to. Sometimes, Premium is paid for additional FAR. FAR/FSI changes as per the width of road (12m or 18m wide). However, the maximum FSI is limited to 2.5 in most of the places.

Municipalities and Planning or development authorities decide FAR.

Check here for other abbreviations used in civil engineering. Also note the information provided is for a general idea and is not specific. Hence, Local municipalities or authorities should be consulted for change of rules etc.

Note, that FAR is also FSI (Floor space index). Some may refer this as percentage and others as ratio similar to FAR.

Find here for More information of FAR/FSI