Floor Area Ratio And Setback distance


The ratio of the permissible built-up area (or floor area) of the building to the area of the plot in which the building is about to be built is called the floor area ratio (FAR).

      FAR = Total built-up Area ( B + C ) / Plot Area ( A)


Here, the sky blue color represents our total plot area.

Key Point: Balcony area does not get included in the total built up area. Only the area surrounded by walls is considered in the total built-up area.

For example : If the plot area is 1000 sq ft, and if the FAR is 1.75, then the total permissible floor area for the building is 1.75 * 1000 = 1750 sq ft. Total permissible built up area is 1750 means, the integration of the total floor area should be 1750. If we wish to build 2 story building of total permissible built up area of 1750 sq ft then, if we have taken the floor area of ground floor area as 1500 sq ft then the floor area of first floor should not exceed 250 sq ft (i.e. 1750- 1500 )  

If we wish to have 3 story building of permissible built-up area of 1750 sq ft, then the foor area of the ground floor + floor area of firrst floor + floor area of second floor <= 1750 sq ft.  

For FAR=1

1000*1= 1000 sq ft

This means we can build a building of area 1000 sq ft. Hence, we can either build a building of one story having area of 1000 sq ft, or we can build a building of 2 story, each story having a area of 500 sq ft, or we can build a building of 4 story having area of each story as 250 sq ft, and so on..

FAR is already fixed by government for particular city or area.

In kathmandu, previously FAR was 1.75, but according to Building Bye Laws, KMC published in 2018, allowable floor area ratio in kathmandu is 3.5.

FAR as defined by Kathmandu Municipality are:

Building Type


Residential building


School, College and University


Star Hotels


Government Buildings


Government Hospitals and nursing home




Setback is the distance measured from the center of the road ( or from the edge of the road) to the pinth beam of the building.

Importance of setback distance:

1.   It is important for the future widening of the road.

2.   It can be used for the parking of the vehicles.

Also, marginal ditance is the distance measured from the plot boundary to the plinth beam of the building.

Marginal distance are also called side setback or rear ( back) setback.

The  certain setback distance is fixed by government for certain city or areas.

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