FAR determines a site’s allowed development as a ratio of building area over lot area. For example, an FAR of 1 would allow a one-story building that covers the entire lot or a two story building that covers half the lot or a three-story building that covers a third of the lot. Regardless of a site’s size, it will have the same allotment of building density as its neighbors.
In urban areas, FARs tend to be high, around 6 or 7 in downtown Washington and around 19 or 20 in midtown Manhattan. To planners and developers, FAR is the most fundamental dimensional standard of a zoning code. It determines a lot’s development potential and hence its value. An FAR of 4 is worth twice as much as an FAR of 2.
FAR is a rational tool, but can be coarse in its application. It allows an infinite variety of building designs, but can’t address the details of setbacks, build-to lines, and human-scale like windows, doors, and materials. FAR controls bulk, but the character of a street comes from the fine grain.
In a suburban landscape diffused by roads and sky, with a changing character and large lots, FAR is only one tool to shape building character. The effect of a six-story building versus an eight-story building will be hard to perceive, but what will be evident is the parking lot in front of it or the odd strip of lawn that surrounds it.