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The Floor Area Ratio (FAR) Calculator helps developers, architects, and planners quickly determine the maximum allowable building area based on zoning regulations and lot size.
FAR is a critical metric in urban planning that controls building density by limiting the total floor area relative to the lot size. Understanding your allowable FAR helps you maximize development potential while ensuring zoning compliance.
Enter your lot dimensions and local FAR limit to instantly calculate your maximum gross floor area, remaining development capacity, and how proposed designs compare to zoning maximums.
Features
Everything you need
- Instant FAR calculations from lot dimensions
- Maximum buildable area determination
- Zoning compliance verification
- Multiple floor configuration analysis
- Remaining development capacity tracking
- Support for FAR bonuses and incentives
- Imperial and metric unit support
How it works
Simple workflow
- 1Enter your lot dimensions or total lot area
- 2Input the applicable FAR limit from local zoning
- 3View your maximum allowable gross floor area
- 4Compare proposed floor areas against the limit
- 5Adjust building footprint and floors to optimize
Use cases
Built for real-world scenarios
Site feasibility studies
Quickly assess development potential for new acquisitions by calculating maximum buildable area.
Zoning variance analysis
Determine how much additional FAR would be needed for proposed designs that exceed base limits.
Density bonus calculations
Calculate the impact of affordable housing or other incentive programs on allowable floor area.
Multi-parcel developments
Analyze FAR across combined lots for planned unit developments and master plans.
FAQ
Frequently asked questions
Floor Area Ratio is the total building floor area divided by the lot area. A FAR of 2.0 means you can build up to twice the lot area in total floor space—for example, a 10,000 sq ft lot could have up to 20,000 sq ft of building area spread across multiple floors.
Divide the total gross floor area of your building by the total lot area. FAR = Total Floor Area ÷ Lot Area. For example, a 15,000 sq ft building on a 10,000 sq ft lot has a FAR of 1.5.
FAR typically includes all enclosed floor areas, but exclusions vary by jurisdiction. Common exclusions include parking structures, mechanical rooms, and certain basement areas. Always verify with local zoning codes.
Residential FAR limits vary widely—from 0.3-0.5 in suburban single-family zones to 10+ in dense urban high-rise districts. Most suburban multifamily zones fall between 1.0 and 3.0 FAR.
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