📐 Floor Area Ratio Calculator
Calculate floor area ratio (FAR) for building projects
Total floor area of all floors combined
Total area of the lot/property
How to Use This Calculator
Select Measurement Unit
Select the unit you'll use for measurements (square feet, square meters, or acres). This determines how the calculator interprets your inputs.
Enter Total Floor Area
Input the total floor area of all floors combined (all stories). This includes all habitable and non-habitable floors in the building.
Enter Lot Area
Input the total area of the lot or property. This is the total land area where the building is located.
Calculate and Review
Click "Calculate Floor Area Ratio" to see FAR, percentage, and area conversions. Use this for zoning compliance and building planning.
Formula
Floor Area Ratio (FAR) = Total Floor Area ÷ Lot Area
FAR Percentage = FAR × 100
Total Floor Area = Sum of all floor areas (all stories)
Lot Area = Total property/land area
Example 1: Single-Story Building (5,000 sq ft floor, 10,000 sq ft lot)
Step 1: Total floor area: 5,000 sq ft
Step 2: Lot area: 10,000 sq ft
Step 3: FAR: 5,000 ÷ 10,000 = 0.5 (50%)
Step 4: This means the building uses half the lot area (typical for single-family homes)
Example 2: Two-Story Building (8,000 sq ft total floor, 10,000 sq ft lot)
Step 1: Total floor area: 8,000 sq ft (4,000 sq ft per floor × 2 floors)
Step 2: Lot area: 10,000 sq ft
Step 3: FAR: 8,000 ÷ 10,000 = 0.8 (80%)
Step 4: This means the building uses 80% of the lot area (2-story building)
About Floor Area Ratio Calculator
The Floor Area Ratio (FAR) Calculator is an essential tool for architects, builders, developers, and property owners who need to calculate floor area ratio for building projects and zoning compliance. This calculator eliminates guesswork by providing precise FAR calculations based on total floor area and lot area, helping you ensure compliance with zoning regulations and plan building projects accurately.
When to Use This Calculator
- Building Planning: Calculate FAR for new building projects
- Zoning Compliance: Verify FAR compliance with zoning regulations
- Building Addition: Calculate FAR for building additions or renovations
- Development Planning: Plan development projects based on FAR limits
- Permit Applications: Calculate FAR for building permit applications
Why Use Our Calculator?
- ✅ Accurate Calculations: Precise FAR calculations for zoning compliance
- ✅ Multiple Units: Supports square feet, square meters, and acres
- ✅ Percentage Display: Shows FAR as both ratio and percentage
- ✅ Area Conversions: Converts areas to different units automatically
- ✅ Comprehensive Results: Shows FAR, percentage, and area breakdown
- ✅ Time Savings: Instant calculations eliminate manual math
Common FAR Limits
Residential: FAR limits vary by zoning, typically 0.5-1.0 for single-family residential, 1.0-2.0 for multi-family residential, and higher for mixed-use developments.
Commercial: FAR limits for commercial properties typically range from 1.0-3.0, with higher limits in dense urban areas and lower limits in suburban areas.
Dense Urban: FAR limits in dense urban areas can be as high as 2.0-5.0 or more, allowing for high-rise buildings and dense development.
Tips for Best Results
- Measure Accurately: Measure total floor area and lot area accurately
- Include All Floors: Include all floors (basements, mezzanines) in total floor area
- Check Local Codes: Always check local building codes and zoning regulations
- FAR Limits: Verify FAR limits for your specific zoning district
- Consult Professional: For complex projects, consult an architect or planner
- Permits: FAR calculations may be required for building permits
Frequently Asked Questions
What is Floor Area Ratio (FAR)?
Floor Area Ratio (FAR) is the ratio of total floor area of a building to the total lot area. It's expressed as a decimal (e.g., 0.5) or percentage (e.g., 50%). FAR is used in zoning regulations to control building density and development intensity.
How do I calculate FAR?
Calculate FAR by dividing total floor area by lot area: FAR = Total Floor Area ÷ Lot Area. For example, if total floor area is 5,000 sq ft and lot area is 10,000 sq ft, FAR = 5,000 ÷ 10,000 = 0.5 (50%). The calculator does this automatically.
What is a good FAR for residential?
A good FAR for residential depends on zoning. Typical limits: 0.5-1.0 for single-family residential (allows single-story on half the lot or two-story on quarter of lot), 1.0-2.0 for multi-family residential. Check local zoning regulations for specific limits.
Does FAR include basements?
FAR calculation depends on local regulations. Some jurisdictions include basements in FAR, while others don't. Some include only habitable basements. Always check local building codes and zoning regulations to determine what's included in FAR calculations.
What if my FAR exceeds the limit?
If your FAR exceeds the limit, you may need to reduce floor area, increase lot area, or apply for a variance or special permit. Consult a zoning professional or planner for guidance on compliance options.
How do I find FAR limits for my property?
FAR limits are specified in local zoning ordinances and building codes. Check with your local planning department or building department. FAR limits vary by zoning district and property type. The calculator provides typical ranges but always verify with local authorities.