FAR =
Floor Area Ratio (FAR), also known as the Site Ratio, Plot Ratio, or Floor Space Ratio (FSR), is the ratio of the gross floor area of a building to the area of the entire site.
Gross floor area is the total floor area of the building, including all stories of the building.
An FAR of 1.5:1 means the building may contain floor area equal to 1.5 times the site area.