Understanding Floor Area Ratio: A Comprehensive Guide
What is Floor Area Ratio?
Floor Area Ratio (FAR) is a critical metric in urban planning and real estate, representing the relationship between the total usable floor area of a building and the total area of the lot where the building stands. A higher FAR often indicates a more densely constructed area.
Local governments use the FAR to implement zoning codes.
How to Calculate the Floor Area Ratio
You can calculate the FAR by dividing the total or gross floor area of the building by the gross area of the lot.
Floor Area Ratio (FAR) = Total Building Floor Area / Gross Lot Area
For example:
- If the total floor area of a building is 10,000 square feet and the lot size is 25,000 square feet, then FAR = 10,000 / 25,000 = 0.40.
What Does the FAR Tell You?
The FAR takes into account the entire floor area of a building, not just its footprint. The calculation excludes unoccupied areas such as basements, parking garages, stairs, and elevator shafts.
Buildings with different numbers of stories can have the same FAR. Local governments regulate FAR to manage urban density and ensure the safety and sustainability of city development.
Due to different safe load factors depending on land use, FAR varies between industrial, residential, and commercial spaces.
A low FAR often deters construction, whereas a higher FAR can help meet growing housing and commercial space demands.
Key Takeaways
- FAR: Relationship of the total usable floor area to the lot’s total area.
- Higher FAR: Indicates denser, urbanized areas.
- Variability: Depends on the building type and local regulations.
Practical Examples of FAR
- A single-story, 1,000-square-foot building on a 4,000-square-foot lot has a FAR value of
0.25x. - A developer has a lot with a FAR of
2.0xand square footage of 1,000 sq ft. They would be allowed to build up to 2,000 sq ft of floor space, which could be divided into two stories of 1,000 sq ft each. - In a real-life scenario, consider an apartment complex in Charlotte, NC. The price is $3 million for 17,350 sq ft on a 78,843 sq ft lot, making the FAR
0.22x.
Comparing FAR and Lot Coverage
While FAR focuses on the ratio of building floor area to lot size, lot coverage takes all structures on the lot into account, including garages, sheds, and nonconforming buildings.
Limitations of FAR
An increased FAR can enhance land value, allowing for spacious rentals or more tenants. However, it may also decrease the value of adjoining properties due to potential obstructions like larger, taller buildings.
Conclusion
Understanding FAR is essential for developers, urban planners, and real estate professionals in planning and optimizing land use. It influences construction decisions, affects property value, and determines the scale of new projects.
Related Terms: zoning codes, real estate, building density, lot coverage.
