Floor area ratio
The floor area ratio (FAR) is a measure of the total permitted floor area of a building, in relation to the total area of the lot (or plot) on which the building stands:
A higher ratio indicates a higher-density environment.
The concept emerged in Europe in the 19th century, and was then taken up in the USA in the 20th century as a form of zoning control for rapidly developing cities. FAR is now often used by urban planners, particularly in the USA, for assessing, or restricting, planning permissions, setting a limit on the 'load factor' generated by new developments, beyond which undue stress is placed on a city and its infrastructure. A low permitted FAR may deter development, whilst a higher FAR allows more usable area, and hence higher potential sales.
The same FAR value can be achieved by buildings with varying numbers of storeys. For example:
1,000 sq. m building with one storey / 4,000 sq. m lot = 0.25
500 sq. m building with two storeys / 4,000 sq. m lot = 0.25
An FAR of 1.0 allows the developer to build a one-storey building over the lot, or a two-storey building over half the lot, or a three-storey building over one-third of the lot, and so on.
An FAR of 2.0 allows the developer to build a two-storey building over the lot, or a four-storey building over half, and so on.
 Related articles on Designing Buildings Wiki
Featured articles and news
What is a residual valuation of land and what does it involve? Have a look at our introductory article.
What will be needed to manage and plan Hinkley Point C successfully?
BSRIA publish new Topic Guide on the issues surrounding Brexit.
Around 6,000 elephants were involved in the construction of the world's largest religious monument, Angkor Wat.
Government publishes new guidance document for landlords about the April 2018 changes.
ICE publish new briefing sheet on municipal energy transmission, retailing, and legislation.
CIOB awards include origami floor joists and BIM MOOC (Massive Open Online Course).
The first CIC briefing of 2017 covered a construction economic forecast, illegal migrant workers, and a Crossrail 2 update.
Have a look at this competition-winning proposal for a new mountain range-like complex in China.
This spherical house in Vienna is considered a micro-nation - the Republic of Kugelmugel.
"Teachers and schools do not understand construction very well" and need to do more, according to Carol Lynch.