Free Setback & Buildable Area Calculator
Calculate the buildable area of a rectangular lot after applying front, rear, and side yard setback requirements from the local zoning code.
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Buildable Area (footprint)
4,425
Total Lot Area9,000
Buildable % of Lot49.2%
Buildable Width59
Buildable Depth75
Max Total Floor Area (all stories)8,850
Buildable Area (footprint) vs Lot Width (feet)
Setback & Buildable Area
Setbacks are the minimum required distances between a building and the property lines. They create the "buildable envelope" that constrains where a structure can be placed on a lot.
Setback Types
Calculating the Buildable Envelope
Buildable Width = Lot Width - (Side Setback x 2) Buildable Depth = Lot Depth - Front Setback - Rear Setback Buildable Area = Buildable Width x Buildable Depth
Additional Constraints
Setbacks define the maximum footprint, but the actual building may be smaller due to:
Example Calculation
75 x 120 ft lot with 25 ft front setback, 20 ft rear setback, 8 ft side setbacks, planning a 2-story home.
- 01Total lot area: 75 x 120 = 9,000 sq ft
- 02Buildable width: 75 - (8 x 2) = 59 ft
- 03Buildable depth: 120 - 25 - 20 = 75 ft
- 04Buildable area: 59 x 75 = 4,425 sq ft
- 05Buildable as % of lot: 4,425 / 9,000 = 49.2%
- 06Max floor area (2 stories): 4,425 x 2 = 8,850 sq ft