Calculate Soffit Panels, Channel, Fascia and Cost
Enter total eave runs and overhang depth, then match the panel dimensions and channel lengths sold by your U.S. supplier.
MATERIAL
Eave and product dimensions
Soffit material estimate
How to calculate soffit material
Soffit area equals total horizontal eave length multiplied by the average projection from wall to fascia. Depth is entered in inches and converted to feet. Waste is applied to area before calculating panel pieces.
The panel calculation uses each piece’s usable width and full length to determine square-foot coverage. This is appropriate for estimating purchases, but a final cut plan should also consider direction, seams, corners, porch returns and manufacturer rules. Channel quantity depends on whether trim is installed at one or both long edges of the soffit run.
U.S. product dimensions
American suppliers commonly list panel and trim dimensions in inches and feet, so those are the primary units. Enter the actual exposed width rather than nominal width. Fascia is reported as linear feet and priced separately because fascia coverage is not the same as soffit area. Round panel and channel pieces up to whole stock units.
Hip roofs, gable returns and porch ceilings can have different depths. Measuring those runs separately improves the cut list and avoids letting one average depth hide a large local shortage.
Does soffit square footage equal roof square footage?
No. Soffit area is the underside of the eave and is calculated from eave length multiplied by soffit depth.