Soffit Calculator
Soffit panels, fascia and vent area for your eaves.
Enter your values
per piece
ⓘ Live results
Results
- Soffit area
- 180 sq ft
- Panels needed
- 12
- Fascia board
- 120 linear ft
- Total vent area required
- 768 sq in
- Soffit intake needed
- 384 sq in (half at the eaves)
- Material cost
- $168.00
Quick answer
Soffit area = eave run × overhang width; building code wants 1 sq ft of net free vent area per 300 sq ft of attic, split half low and half high.
soffit area = run × overhang
How to use the Soffit Calculator
- 1Measure the total eave run around the house.
- 2Enter the overhang width in inches.
- 3Add the attic floor area to size the ventilation.
Inputs explained
- Panel coverage(sq ft)
- per piece
Worked example
Using the values the calculator loads with:
Inputs
- Total eave run120 ft
- Overhang width18 in
- Attic floor area1600 sq ft
- Panel coverage16 sq ft
- Price per panel14 $
Results
- Soffit area180 sq ft
- Panels needed12
- Fascia board120 linear ft
- Total vent area required768 sq in
- Soffit intake needed384 sq in (half at the eaves)
- Material cost$168.00
Frequently asked questions
How much soffit venting do I need?
1 sq ft of net free area per 300 sq ft of attic, with half at the soffit and half at the ridge.
Is vented soffit needed everywhere?
Continuous vented panels work best, but alternating vented and solid panels is acceptable if the total net free area is met.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.