Floor area ratio (FAR) is the ratio of a building's total floor area
(gross floor area) to the size of the piece of land upon which it is
built. The terms can also refer to limits imposed on such a ratio
As a formula FAR = (gross floor area) / (area of the plot)
1.1 Regional variation
3 Purpose and use
4 Impact on land value
8 External links
Floor Area ratio is sometimes called floor space ratio (FSR), floor
space index (FSI), site ratio or plot ratio
The difference between FAR and FSI is that the first is a ratio, while
the latter is an index. Index numbers are values expressed as a
percentage of a single base figure. Thus an FAR of 1.5 is translated
as an FSI of 150%.
The terms most commonly used for this measurement vary from one
country or region to the next.
In Australia floor space ratio (FSR) is used in New South Wales and
plot ratio in Western Australia.
India floor space index (FSI) and floor area ratio (FAR) are both
United Kingdom and
Hong Kong both plot ratio and site ratio are
Singapore the terms plot ratio add gross plot ratio (GPR) are more
In the United States and Canada, floor space ratio (FSR) and floor
area ratio (FAR) are both used.
Use ratios are used as a measure of the density of the site being
developed. The ratio is generated by dividing the building area by the
parcel area, using the same units.
One of the purposes of the 1916 zoning ordinance of New York City was
to prevent tall buildings from obstructing too much light and air. The
1916 zoning ordinance sought to control building size by regulating
height and setback requirements for towers. In 1961, a revision to the
zoning ordinance introduced the concept of floor area ratio (FAR).
Buildings built before 1961 often have FARs that would be unachievable
today, such as the
Empire State Building
Empire State Building which has an FAR of 25 -
meaning that it earns considerably greater rent than a newer building
on the same land could hope for.
Purpose and use
The floor area ratio (FAR) can be used in zoning to limit urban
density. While it directly limits building density, indirectly it also
limits the number of people that a building can hold, without
controlling a building's external shape.
For example, if lot must adhere to a 0.1 FAR, then the total area of
all floors in all buildings on the lot must be no more than one-tenth
the area of the parcel itself. In other words, if the lot was 10,000
sq. ft, then the total floor area of all floors in all buildings
mustn't exceed 1,000 sq. ft.
An architect can plan for either a single-story building consuming the
entire allowable area in one floor, or a multi-story building that
rises higher above the plane of the land, but which must consequently
result in a smaller footprint than would a single-story building of
the same total floor area. By combining the horizontal and vertical
limits into a single figure, some flexibility is permitted in building
design, while achieving a hard limit on at least one measure of
overall size. One advantage to fixing this parameter, as opposed to
others such as height, width, or length, is that floor area correlates
well with other considerations relevant to zoning regulation, such as
total parking that would be required for an office building, total
number of units that might be available for residential use, total
load on municipal services, etc. The amounts of these things tend to
be constant for a given total floor area, regardless of how that area
is distributed horizontally and vertically. Thus, many jurisdictions
have found it unnecessary to include hard height limitations when
using floor area ratio calculations.
Common exclusions to the total calculation of square footage for the
purpose of floor area ratio (FAR) include unoccupied areas such as
mechanical equipment floors, basements, stair towers, elevator shafts,
and parking garages.
Japan has extensively adopted the floor area ratio in the zoning
system since 1970. The evaluation of the adoption is, however,
controversial: some say that it has deteriorated the skylines and
building lines in Japanese cities; others[who?] claim that it has
protected the residential environments.
India FAR and FSI are both used. FAR regulations vary from city to
city and generally it is from 1.3 to 3.25. In Mumbai 1.33 is the norm
but higher FSI is allowed along the Metro rail line and slum areas
like Dharavi. In Bangalore, 40 feet streets allow only an FAR of 1.75
but 100 feet streets allow 3.25 FAR.
Impact on land value
FAR has a major impact on the value of the land. Higher allowable FAR
yields higher land value.
Andres Duany (2000)[full citation needed] notes:
Abdicating to floor area ratios (market forces) is the opposite of
aiming a community toward something more than the sum of its parts.
FAR, a poor predictor of physical form, should not be used when the
objective is to conserve and enhance neighborhood character; whereas
traditional design standards (height, lot coverage and setbacks or
build-to lines) enable anyone to make reasonably accurate predictions,
recognize violations, and feel secure in their investment decisions.
If FAR is carelessly combined with traditional setbacks, assembled
lots have a considerable advantage over individual lots, which has a
negative effect on fine-grained cities and the diversity of ownership.
^ NSW Department of Planning, retrieved 19 August 2010
^ Quick Start Guide to Town Planning in the City of South Perth ,
retrieved 19 August 2010
^ University of Dundee: Town and Regional planning, retrieved 19
^  
Zoning - Glossary". nyc.gov. Retrieved July 31, 2015.
^ Willis, Carol (1992). Ward, David; Zunz, Olivier, eds. "Form follows
finance: The Empire State Building". Landscape of Modernity: Essays on
New York City, 1900-1940. New York City: Russell Sage Foundation:
^ Kerr, Alex. Dogs and Demons. New York: Hill and Wang, 2001. pp
Meriam, Dwight (2004). The Complete Guide to Zoning. McGraw-Hill.
Birch, Eugenie L. (2009). "The Urban and Regional Planning Reader".
Routledge. ISBN 0-415-31997-8
An explanation of the floor area rati