How to Calculate FAR in NYC

Basic FAR Calculation

FAR = Maximum Allowed Floor Area / Lot Area

Or inversely: Maximum Allowed Floor Area = Lot Area x FAR

Example 1: Simple Residential

A 2,500 sq ft lot in an R6 district (FAR 2.43 for residential):

• Maximum Floor Area = 2,500 x 2.43 = 6,075 sq ft
• This could be a 3-story building with ~2,025 sq ft per floor
• Or a 4-story building with ~1,519 sq ft per floor

Example 2: Commercial Mixed-Use

A 10,000 sq ft lot in a C4-6 district (FAR 10.0 commercial, 10.0 residential):

• Maximum Floor Area = 10,000 x 10.0 = 100,000 sq ft
• With inclusionary housing bonus: up to 12.0 FAR = 120,000 sq ft
• Could be a 20-story mixed-use building

What Counts as Zoning Floor Area

Not all building space counts toward FAR. The Zoning Resolution (ZR 12-10) defines "floor area" as the sum of gross areas of all floors, with specific exclusions:

• Included: All habitable floor area, enclosed parking above grade, mechanical space above allowable deductions
• Excluded: Cellars (if less than 50% above curb level), up to 200 sq ft of mechanical per dwelling unit, open balconies, terraces, outdoor recreation space

FAR by Common Zoning Districts

• R1/R2: 0.5 FAR (single-family detached)
• R3-R5: 0.5-1.25 FAR (low-density residential)
• R6-R7: 0.78-4.0 FAR (medium-density residential)
• R8-R10: 4.0-10.0 FAR (high-density residential)
• C1-C4: 1.0-10.0 FAR (commercial, varies widely)
• C5-C6: 4.0-15.0 FAR (high-density commercial)
• M1-M3: 1.0-10.0 FAR (manufacturing)

Unused FAR (Development Rights)

If your building uses less FAR than allowed, the difference is unused development rights (commonly called "air rights"). These rights have monetary value and can potentially be transferred to adjacent lots through zoning lot mergers.

Calculating Unused FAR

Unused FAR = Allowed FAR - Built FAR

Example: 5,000 sq ft lot in R7A (FAR 4.0). Building has 12,000 sq ft of floor area.

• Allowed: 5,000 x 4.0 = 20,000 sq ft
• Built: 12,000 sq ft
• Unused: 8,000 sq ft of development rights