What is a Floor Area Ratio (FAR) and Why is FAR Important to Urban Design?

By Dom Nozzi

What is a “floor area ratio”? (sometimes called “FAR”)

Perhaps the best way to define an FAR is to give an example. An FAR of 1.0 means that the developer is allowed to build the equivalent of a one-story building over her entire lot, or a 2-story over half the lot. An FAR of 2.0 means the developer is allowed to build the equivalent of a two-story building over her entire lot, or a 4-story over half the lot.

An FAR of 0.5 means the developer is allowed to build the equivalent of a one-story building over half her entire lot, or a 1-story over half the lot.

And so on.

I should hasten to point out that while the FAR examples given above that exceed 1.0 may seem very dense, keep in mind that in almost every case except in, say, the middle of a downtown, an FAR of 1.0 would not allow the developer to build one story over the entire lot, as other local development code regulations would also require space for landscaping/open space, parking, setbacks, etc. Thus, an FAR of 0.8 would almost never result in a one-story building over 80% of the lot. It would probably be a one-story over less than 80% to be able to fit in the landscaping, etc., or a two-story over even less of the lot. In effect, what FAR limits do is control the amount of building floor area, and often don’t really tell you how much of the site will be covered by a building.

Walkable urbanism and healthy transit require FARs to be at least 1.5 to 3.0. In Europe, those loveable cities we all love to walk have FARs that are probably well over 3.0. In America, as you can imagine, most of our commercial areas have tiny developed FARs of about 0.1 (with most space taken up by surface parking).

Therefore, if a community wishes to encourage more walking and vibrant, sociable urbanism, it should require at least 1.5 FAR. Anything less than about 1.0 locks a community into sprawl, unwalkable and unlovable design, extreme auto dependence and downwardly spiraling downtowns, because low FARs create unwalkably large spaces that are more car-scaled than people-scaled.

People feel more comfortable in the quaint, enclosed spaces created by, say, 2.0 FAR development patterns. They feel exposed and in a “no-man’s-land” when FARs are less than 1.0 (which is fine if you are inside an SUV…)

Note that I am not suggesting that we require more than 1.5 FAR everywhere in a community. Only in in-town places where more walking and urbanism are being promoted do we want to see 1.5 FAR or more. In suburban and rural locations (where less is better), it is generally okay to have an FAR of 0.5 or less—unless you are trying to create a walkable neighborhood center (a sea-of-asphalt shopping center that is to be transformed, for example) in the middle of a suburban location.

Here is an excerpt from the Urban Design Toolbox I wrote in 2003:

Higher densities make it possible for people to walk, bicycle, or use the bus.  One important way to increase development densities is to increase the allowable floor area ratio (FAR).  FAR is a measure of how much square footage can be built on a given piece of land. In commercial areas, FAR should be at least 1.0. In office/industrial & mixed use areas, it should be at least 1.25 (Snohomish County WA).  

Richard Untermann, a well-known urban designer, calls for FARs of 2.0-3.0 in town centers, and 3.0 for office areas.  San Diego requires at least 0.5 FAR near bus stations.  To increase employment densities, Orlando requires both a minimum and maximum FAR for most commercial zoning.  

Unfortunately, while an FAR of 1.0-2.0 is considered ideal for creating transportation choices, most towns allow less FAR than this in their town centers.  Every 20 percent increase in floor space in commercial centers developed as non-office uses is associated with a 4.5 percent increase in ride sharing and transit use, according to studies I have seen.

My latest book, The Car is the Enemy of the City (WalkableStreets, 2010), can be purchased here.

 Visit my urban design website read more about what I have to say on those topics. You can also schedule me to give a speech in your community about transportation and congestion, land use development and sprawl, and improving quality of life.

 Visit: http://www.walkablestreets.com Or email me at: dom@walkablestreets.com