Soffit Calculator
Calculate soffit panels, J-channel, and fascia needed for roof overhang enclosures. Enter perimeter and overhang width.
๐๏ธ Soffit Calculator
Results
Soffit Area120.00 sq ft
Soffit Panels (12 ft)10 panels
J-Channel240.00 lin ft
Fascia120.00 lin ft
๐ก How to Calculate Soffit Materials
Soffit covers the underside of the roof overhang. Area = perimeter ร overhang width. Standard soffit panels are 12 inches wide by 12 feet long. Vented soffit provides attic ventilation โ use it for at least 50% of soffit area.
J-channel runs along both edges (wall side and fascia side) โ so you need twice the perimeter in J-channel. Fascia board covers the vertical face of the overhang, matching the perimeter length. F-channel can replace J-channel where soffit meets the wall.
A house with 120 ft perimeter and 12-inch overhang: soffit area = 120 sq ft. With 12-inch ร 12-ft panels: 10 panels. J-channel: 240 lin ft. Fascia: 120 lin ft.