Soffit Calculator
Estimate soffit area and panels for eaves and overhangs.
Enter your total eave length and the overhang depth to get the soffit area, then pick a panel type to see how many 12-ft vinyl panels or 4 × 8 sheets to buy. The price field is editable, so plug in your local panel cost for a working budget.
How it works
Soffit area is eave length × overhang depth (converted to feet). The calculator adds your waste allowance, divides by the coverage of the panel you chose — 12 sq ft for triple-4 vinyl, 16 sq ft for quad-4, 32 sq ft for a 4 × 8 sheet — and rounds up to whole panels. Add a panel or two on top if your roofline has lots of corners or short runs, since offcuts often can't be reused.
Frequently asked questions
How do I measure for soffit?
Soffit area is total eave length × overhang depth. Walk every eave (and any rake you're covering) and measure the horizontal distance from the wall out to the fascia. For example, 120 ft of eaves with a 16-inch overhang is about 160 sq ft of soffit.
What sizes do soffit panels come in?
Vinyl soffit usually comes in 12-ft lengths at 12-inch (triple-4) or 16-inch (quad-4) widths — 12 or 16 sq ft per panel. Sheet soffit in plywood or fiber cement is typically 4 × 8 ft, covering 32 sq ft.
Should I use vented or solid soffit?
Mix them. Vented panels supply the attic's intake air; a common rule is 1 sq ft of net free vent area per 150 sq ft of attic floor, split between soffit intake and ridge or gable exhaust (1 per 300 with a balanced system and a vapor barrier). Use solid panels where venting isn't needed, like porch ceilings.
Do I include gable (rake) overhangs?
Yes, if you're covering them — measure each rake's length times its overhang depth and add it to the total. Rake soffits are usually solid panels, since they don't ventilate the attic the way eave soffits do.
Is this calculator free and private?
Yes. Every CubicCabin calculator runs entirely in your browser, so the numbers you enter are never uploaded or stored. There's no sign-up, no limits, and it keeps working even if you lose connection after the page loads.