Floor Area Ratio (FAR)

Introduction:

The Floor Area Ratio (FAR) is the main regulating component that controls the overall sizes of buildings. FAR is the total ratio of the total buildable floor area to the area of its zoning lot. Typically, each zoning area in different cities or towns has different FAR rules that produce the max buildable area.

Example

Lot A has an area of 17,500 SF. This is the ‘lot area’, or ‘zoning lot area’. The lot in this example is listed as having a maximum FAR of 25. This means that the maximum buildable area is 25 * 17,500 SF = 437,500SF.

Maximum

FAR values establish the maximum size a building may be, however, it is reasonable to expect many buildings to be below this value for various reasons. Even for designs that are attempting to maximize the building area, there is typically a small % leftover for contingency in design needs.

Per Floor

Another way to think of FAR is to think about each FAR integer value equaling one floor of buildable area. However, this is rarely the case. Even with high rises in dense cities, towers step back from edges or leave room for other areas whether designed, or per zoning requirements.

• An FAR of 25 would mean a building maxing out its FAR and creating a building with its buildable area encompassing the entire site, would have 25 floors of building.
• An FAR of 25 with 50% of lot coverage for every floor, would mean a building that is 50 stories tall.