Gross Floor Area Calculator

GFA Calculator
Enter lot size in square feet
Maximum Gross Floor Area
for Post-FAR Buildings (a)
Maximum Gross Floor Area
for Pre-FAR Buildings (b)

(a) "Post-FAR Building" means a single-family dwelling that was not lawfully in existence before February 7, 1989, or that was constructed since 1989.
(b) "Pre-FAR Building" means a single-family dwelling that was lawfully in existence before February 7, 1989.

Note: This calculator is for properties zoned for single family residences (R1,R2,R3,R4,R5) and is for estimation purposes only. For exact numbers, please contact the community development department to request a zoning analysis to be completed with a plat of survey.

For a detailed description of methodology of calculating the Gross floor area, Roofed Lot Coverage and Impermeable Surface coverage of existing or proposed construction, consult both the Single family residential Zoning Calculation Worksheets and the Winnetka Zoning Ordinance/Title 17.