Spray Foam Calculator

Spray Foam Board Foot Calculator

Calculate spray foam board feet, square footage, R-value, and DIY kit requirements for open cell and closed cell spray foam insulation.

Spray Foam Calculator

Calculate coverage for spray foam insulation kits

Foam Type

Length (feet)

Width/Height (feet)

Thickness (inches)

Waste Factor (%)

Note: Spray foam expands 30-100× its liquid volume. One board foot of cured foam covers 1 sq ft at 1" thick.

Closed Cell Foam

R-6 to R-7 per inch. Vapor barrier, structural strength. Best for exterior walls, roofs, and moisture-prone areas. More expensive.

Open Cell Foam

R-3.5 to R-4 per inch. Sound dampening, lower cost. Good for interior walls, attics (with vapor retarder), and soundproofing.

DIY Kits

Common sizes: 200 BF, 600 BF. At 2" thick, a 600 BF kit covers ~300 sq ft. Add 15-20% for waste and learning curve.

Frequently Asked Questions

How do I calculate spray foam board feet?

Board feet = Square feet × Thickness (inches). For a 100 sq ft wall at 2" thick: 100 × 2 = 200 board feet required.

What R-value do I need?

Depends on climate zone. Typical: R-13 to R-23 for walls (2-3" closed cell), R-38 to R-60 for attics (6-10" open cell).

How much waste should I plan for?

15-20% for experienced users, 25-30% for DIY beginners. More waste in complex areas with many corners and penetrations.

Specialized Calculators

Choose from our collection of specialized board foot calculators tailored for specific materials and applications

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