How to calculate floor area ratio ( FAR ) for a building?

 What is the floor area ratio?

The floor area ratio is the ratio of a building's total floor area to the area of land or plot upon which the building is constructed.

FAR is fixed by the local governing authority & it varies depending upon the region & locality.

FAR = [Total covered area of all floors/area of land or plot. ]

Let us go through the examples to understand the FAR concept clearly.

Examples:

1. Calculate the FAR of a building having 3 floors built over 1200 sq ft. area. The area of each floor is 650 sq ft.

FAR = [total floor area ➗ area of plot]

Here, the total floor area

= [area of each floor х no. of floors]

= [650 sq ft. х 3 nos.]

= 1950 sq ft.

FAR = [ 1950 sq ft. ➗ 1200 sq ft.]

  FAR  = 1.625 

Note:

In some parts of the country, FAR is also denoted in percentages.

 FAR 150% or simply 150 is equivalent to FAR = 1.5. In this city, you can construct a building having a covered area of 1.5 times your plot. 

2. Calculate the total floor area of the building which you can construct over the plot of size 50ft.х 80ft. The permitted FAR of that particular city is 2.

FAR = [total floor area ➗ area of plot]

2 = [ total floor area ➗ (50ft. х 80 ft.)]

Total floor area = [2  х (50ft. х 80 ft.)] 

      Total floor area  = 8000 sq ft.

3. A plot owner wants to construct a building having 4 floors over the plot area of 4000 sq ft. The FAR of the locality is 2.5. What will be the covered area of the building, if all the floors are constructed having the same area? 

The total floor area that can be constructed 

   = [FAR  х plot area.]

 = [ 2.5 х 4000 sq ft.]

 = 10,000 sq ft.

The total area covered by the building 

= [total floor area ➗ no. of floors]

= [10,000 sq ft. х 4 nos.]

= 2500 sq ft.

To go through the articles on Estimation & calculation in civil engineering, click here.

Thank you for going through these calculation steps❤. Have a good day 😄.

    

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