In many places in the United States and world, other regulations, such as height limits, will further limit how FAR can be apportioned in a development. Without other development constraints, FAR would offer a great deal of flexibility in the final shape of a building. The second calculation is determined by calculating the floor area, again in square feet, of each story of the building and then adding up the area of each floor to determine the gross, or total, floor area of the building.ĭividing the gross floor area by the buildable land area produces the Floor Area Ratio (FAR). Which regulatory implications and other encroachments determine the buildable land area is subject to some variety between specific, local zoning codes and land use regulations. Many encroaching factors can limit the buildable land area, like public streets and other public rights-of-way, wetlands or streams, and regulatory limitations. Buildable land area is the portion of a development site where construction can legally and reasonably occur. To calculate FAR, the first component is a measurement of the buildable land area, measured by square feet, for the entire site, parcel, or lot. Component Calculationsīecause FAR is a ratio, understanding the term requires an understanding of the components of this ratio. A Planning Advisory Services (PAS) report from the American Plan Association, published in 1958, explains more about the genesis of FAR as a common tool for plan implementation. The first zoning codes were created to limit the bulk of buildings, but floor area ratio emerged later as an innovation in how zoning codes accomplished the goal of limiting development intensity. So, for example, in many cities, the vast majority of residential zones are set for very low FARs, and the vast majority of the commercial and office uses allowed in the downtown area will have higher FARs. The allowable FAR set by zoning codes can vary greatly depending on the corresponding land use. In some cases a large FAR is considered a development incentive, and thus a tool of economic development. In the United States, however, FAR has most frequently been used to limit the intensity of land use or to control the mass and scale of development. Zoning codes set the FAR at ratios commensurate with a desired outcome for future development-when FAR is larger, more, larger developments are desired. FAR is usually expressed as a decimal number.įloor area ratio (FAR) is one of the most common regulatory metrics in city planning, and is thus critical to understanding how plans and zoning codes determine the future of the built environment. Floor area ratio (FAR) is a measurement that quantifies the intensity of development by calculating the ratio of a building's total floor area (or gross floor area) in proportion to the size of the piece of land upon which it is built.

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