Floor Area Ratio: Definition, Calculation Formula, Examples, and Applications

An in-depth guide to Floor Area Ratio (FAR), covering its definition, calculation formula, examples, historical context, and its applications in real estate and urban planning.

Definition

Floor Area Ratio (FAR) is a measure used in urban planning and real estate development to denote the relationship between a building’s total usable floor area and the total area of the plot of land on which it is built. FAR is used to regulate building density and ensure balanced development. It is a crucial metric for urban planners, architects, and developers.

Calculation Formula

The formula to calculate Floor Area Ratio is straightforward:

$$ \text{FAR} = \frac{\text{Total Usable Floor Area}}{\text{Total Lot Area}} $$

where:

• Total Usable Floor Area refers to the sum of all floor areas of a building, including all floors.
• Total Lot Area is the area of the land parcel on which the building is situated.

Example Calculation

For example, if a building has 10,000 square feet of total usable floor area and is built on a lot that is 2,000 square feet, the FAR would be:

$$ \text{FAR} = \frac{10,000 \text{ sq ft}}{2,000 \text{ sq ft}} = 5.0 $$

This indicates that the building’s total floor area is five times the size of the lot area.

Historical Context

The concept of FAR originated in the early 20th century and has been integral to urban planning for managing building densities, improving livability, and ensuring that infrastructures like roads, parks, and utilities can support new developments. The application of FAR has evolved over time alongside advances in architectural design and urban policy.

Applications in Urban Planning and Real Estate

Regulation and Compliance

In many jurisdictions, FAR is regulated by zoning laws to control the density of development and preserve open space. High FAR values are typically allowed in central urban districts, encouraging vertical development, while lower FAR values are common in suburban and rural areas.

Impact on Property Value

FAR can significantly impact the value of a property. Higher FAR values can be more valuable as they allow for more extensive development, which can lead to higher rental and sale revenues.

Sustainable Development

FAR is also used to promote sustainable development by encouraging the efficient use of land. By limiting the expansion of built areas, FAR regulations can contribute to reducing urban sprawl, preserving green spaces, and supporting the creation of walkable communities.

Comparing FAR with Related Metrics

Building Coverage Ratio (BCR)

Unlike FAR, BCR measures the proportion of land covered by the building’s footprint, excluding upper floors. BCR is calculated as:

$$ \text{BCR} = \frac{\text{Building Footprint Area}}{\text{Total Lot Area}} $$

Plot Ratio

Plot Ratio is another term often used interchangeably with FAR but can sometimes have different regulatory implications based on regional planning policies.

FAQs

What factors can influence FAR limitations?

Factors influencing FAR include local zoning regulations, urban density requirements, architectural design criteria, and community planning goals.

How can FAR be modified or adjusted?

In some cases, developers can seek variances or special permissions from local planning authorities to increase or decrease the FAR, based on the project’s specific needs and community benefits.

Can FAR influence building design?

Yes, FAR can shape building design by encouraging vertical development and the efficient use of space, often leading to multi-story buildings and innovative architectural solutions.

References

1. Urban Land Institute. The Dimensions of Urban Design. Washington, DC: ULI, 2002.
2. American Planning Association. AICP Handbook, 2021.
3. Watson, Donald. Time-Saver Standards for Urban Design. New York: McGraw-Hill, 2003.

Summary

The Floor Area Ratio (FAR) is a fundamental metric in real estate and urban planning, playing a critical role in managing building density, influencing property values, and promoting sustainable development. Understanding how FAR is calculated and applied helps stakeholders make informed decisions about land use and infrastructure development.