What is floor area ratio?

The ratio between the overall area of the plot and the overall area of the building is called the floor area ratio (FAR). The term is better known by the name Floor Space Index (FSI).  The FAR guidelines differ from one place to another. In India, FAR guidelines depend on the National Building Code. 

The different cities have different FAR values which depend on the space.The municipality determines the FAR limit in every city.If the FAR guidelines are violated it can pressurize the city and can cause harm. FAR rules change according to the population, residential, non-residential, commercial, non-agricultural land.

How to calculate FAR?

You can calculate the FAR by the formula I have provided below:

Floor Area Ratio (FAR) = Total Building Floor Area/ Total area of plot

To know what is a good floor area ratio you need to understand how to calculate FAR. By dividing the total built-up area of all the floors and total built-up area of the plot on which the building is created you get the result of FAR. For example, if I have land which is 2000 square feet in area and I want to construct a residential building I can take up to 3000 sq. ft of the covered area of the plot as the FAR of my locality is 1.5.

FAR= Total area of building/ total area of plot= 3000/2000= 1.5

Now you might be wondering how I can take up 3000 sq.ft but I have land which is only 2000 sq.ft. Well, I can construct two floors in a building which should not exceed more than 3000 sq.ft. Areas such as the staircase, and other structures will fall under 3000 sq.ft. I hope you understand now what is a good land to building ratio and get a clear idea about what is floor area ratio.

There are some other aspects about

what is a good floor area ratio I will share with you briefly:

If the value of FSI is less than 1.5 you don’t need to worry about FSI guidelines. I will provide you with some pointers for a better understanding.

1. Buildings:

The FSI guidelines are not applicable if the minimum plot extent is 80 sq.m or the width of the road is below 6m if a residential building has less than two floors or six dwelling units. The FSI value for these buildings ranges between 1.37 to 1.43. Therefore you don’t need to worry about FSI guidelines.

1. Special buildings:

Even if your residential building has 6 dwelling units and has more than two floors you don’t need to worry about FSI guidelines if the area of the plot is 200 sq.m or below and the minimum road width is below 9m. Here the FSI that will be achieved is less than 1.5 because of the setbacks and height regulations. FSI guidelines will be effective for plot sizes more than 700 sq.m and above.

1. Group Development:

If you own a commercial or residential plot which is smaller than 660 sq.m, then the FSI guidelines are not applicable. The minimum road width should be 10m. The achievable FSI in these plots ranges between 1.0 and 1.8 hence FSI is not affected in these plots.

1. Multi-storeyed building:

The FSI of a multi storey building should be between 2 and 3.5. If a plot area is between 1,200 sq.m to 15,00 sq.m this FSI value is easily achievable. Therefore, the FSI guidelines would not be violated.

A good floor ratio varies from different localities in the cities. In metropolitan areas the FAR value ranges from 1.25 to 3.

I hope my answer on

what is floor area ratio

  was helpful.

The Floor area ratio for residential building is a crucial urban planning metric that regulates the density of development in a particular area. It represents the ratio between a building's total floor area and the size of the lot on which it is built. A higher FAR indicates a denser and more urbanized development, while a lower FAR indicates a less dense and more suburban or rural setting.

Optimal FAR for Residential Buildings

The optimal FAR for residential buildings depends on various factors, including the desired density, infrastructure capacity, environmental considerations, and neighbourhood character. However, a general guideline suggests a FAR range of 2.0 to 4.0 for urban residential areas, 0.5 to 2.0 for suburban residential areas, and 0.25 to 0.5 for rural residential areas.

What is Floor Area Ratio Formula?

Here is the formula for FAR:

FAR = Total floor area ÷ Total area of the lot

For example, if a building has a total floor area of 10,000 square feet and the lot it is built on is 5,000 square feet, then the FAR would be 2.0. This means that the building has twice as much floor area as the lot it is built on.

FAR is used by municipalities to control the density of development in a particular area. A higher FAR generally means that there will be more development in an area, while a lower FAR means that there will be less development.

FAR is also used by developers to determine how much floor area they can build on a particular lot. A developer with a lot with a FAR of 2.0 could build a building with up to 20,000 square feet of floor area.

The specific FAR requirements for a particular area will vary depending on the municipality. However, the general principle is that FAR is used to control the density of development and to ensure that there is enough open space in an area.

Now you know the floor area ratio for residential building.