FSI Explained: Why It Matters & How to Calculate It Accurately

Floor Space Index, commonly referred to as Floor Area Ratio, is a parameter in construction that basically refers to how much of the built-up area can be constructed on a particular plot of land. The concept of FSI ensures orderly growth without congestion and provides a proper balance between open space and buildings in rapidly growing cities. The need to understand FSI for home owners, builders, and investors arises because FSI directly influences project cost, building height, design, and future resale value. The calculation for FSI is quite straightforward: FSI = Total Built-Up Area / Total Plot Area For instance, if the plot area is 1,000 sq. ft. and the permissible FSI is 2.0, you can construct up to 2,000 sq. ft. of total floor area. This includes all floors combined. Local building authorities decide the FSI based on road width, zoning regulations, and infrastructure facilities available in the area.