Calculate how much soffit you need for your project. Get panel counts, ventilation requirements, and cost estimates for vinyl, aluminum, or wood soffit.
📏 Quick Formula
Soffit Area = Eaves Length (ft) × Overhang Depth (ft) Example: 100 ft eaves × 1 ft depth = 100 sq ft of soffit needed
📐 Enter Measurements
Measure all walls where soffit will be installed
📦 Materials Needed
Soffit Panels Needed
0 panels
(includes 10% for waste)
Total Soffit Area0 sq ft
Panels (no waste)0 panels
J-Channel (wall side)0 linear ft
F-Channel (fascia side)0 linear ft
💡 Tip: Most soffits use a mix of vented (50%) and solid (50%) panels for proper attic ventilation.
📋 Soffit Panel Size Reference
Panel Type
Width
Length
Coverage
Best For
Triple 3
12"
12 ft
12 sq ft
Most common
Quad 4
16"
12 ft
16 sq ft
Wider overhangs
Double 5
10"
12 ft
10 sq ft
Narrow overhangs
📏 How to Measure for Soffit
1
Measure Eaves Length
Walk around your home and measure along each wall where soffit will be installed. Add all lengths together.
2
Measure Overhang Depth
Measure from the wall to the outer edge of the fascia board. This is typically 8"-24" for most homes.
3
Calculate Total Area
Multiply total eaves length by overhang depth (in feet). Example: 150 ft × 1 ft = 150 sq ft.
4
Add 10% for Waste
Always order extra for cuts, mistakes, and future repairs. Multiply your panels by 1.1.
🏠 Soffit Materials Comparison
Vinyl
$1-$3/sq ft
✓ Affordable • Low maintenance • Won't rot
✗ Can crack in cold • Limited colors
Aluminum
$3-$6/sq ft
✓ Durable • Fire resistant • Many colors
✗ Can dent • More expensive
Wood
$4-$8/sq ft
✓ Classic look • Paintable • Strong
✗ Requires maintenance • Can rot
💰 Installation Cost Guide
Vinyl Soffit
$6-$10/linear ft
Aluminum Soffit
$8-$14/linear ft
Wood Soffit
$10-$16/linear ft
* Includes material and professional installation
💡 Pro Tips
Use vented panels every few feet for airflow
Match soffit color to fascia or trim
Install during mild weather (40-80°F)
Check local codes for vent requirements
Replace damaged panels promptly
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To calculate soffit needs: (1) Measure the total length of all eaves where soffit will be installed, (2) Measure the overhang depth from the wall to the fascia, (3) Multiply length × depth to get total square footage, (4) Divide by panel coverage area and add 10% for waste. For example, 100 ft of eaves with 12" overhang = 100 sq ft of soffit needed.
Soffit installation costs $6-$16 per linear foot installed, depending on material. Vinyl soffit costs $6-$10/ft installed, aluminum costs $8-$14/ft, and wood costs $10-$16/ft. Material alone costs $1-$8 per square foot. A typical home with 200 linear feet of soffit costs $1,200-$3,200 for professional installation.
Calculate soffit vents using the 1/150 or 1/300 rule: Divide your attic floor area by 150 (no roof vents) or 300 (with roof vents) to get total vent area in square feet. Convert to square inches (×144). Soffit vents should provide 50% of total ventilation. Divide by the net free area of each vent (typically 50 sq in for standard vents) to get the number needed.
Linear feet for soffit equals the total length of all eaves around your home. Measure along each wall where soffit will be installed: front, back, and both sides. For a 40×30 ft house, that's 40+40+30+30 = 140 linear feet. Don't forget to include garage eaves and any architectural features like dormers or bay windows.
Vented soffit has perforations or slots that allow air to flow into the attic for ventilation, while solid soffit has no openings. Most homes need a combination: vented panels near the roof edge for airflow and solid panels closer to the wall. A common ratio is 50% vented and 50% solid, though some codes require all vented panels.
J-channel runs along the wall where soffit meets siding (equals eaves length). F-channel (or fascia channel) runs along the fascia board (also equals eaves length). For 100 ft of eaves, you need approximately 100 ft of J-channel and 100 ft of F-channel. Add 10% for waste and corners.
📐 Disclaimer: These calculations are estimates based on standard panel sizes and typical installation costs. Actual material needs and costs may vary based on your specific roof design, local prices, and contractor rates. Always get multiple quotes and verify measurements before purchasing materials.