Spray Foam Insulation Calculator
Spray foam is sold in board feet — one square foot at one inch thick. Enter your area and target thickness to size the job, count kits, and compare DIY against a contractor.
Your project
Covers cuts, compression and odd bays. 10% is the usual default.
Your results
- Board feet required
- 1,980 bd ft
- R-value achieved
- R-19.5
- DIY kits needed
- 4 × 600 bd ft kits
- DIY kit cost
- $3,600
- Contractor estimate
- $2,673
Sprayed, typical range
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
Spray Foam Insulation Kit
BEEST FullStop Spray Foam Insulation Kit - 240 Board ft/sq.ft. Fire Rated Spray Insulation Foam for Walls & Attics with Thermal & Soundproofing - Includes 12x Cans, 1 Cleaner, Pro X Gun, Safety Gear
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12 Pack Amptern Spray Foam Insulation Kit, 240 Board Ft High Density Closed Cell Spray Foam for Walls & Attics with Thermal & Soundproofing, Complete DIY Spray Gun Set
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BEEST FullStop Spray Foam Insulation Kit for Walls and Attic - Fire Rated - 720 Board ft/sq.ft Perfect Heat & Acoustic Insulation - 36x Spray Foam Can, 2X Cleaner, Pro Gun & Safety Gear
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Spray Foam Sealant Gaps And Cracks
Loctite Tite Foam Gaps & Cracks Spray Foam Sealant, 12 fl oz Can, 1 Pack - Polyurethane Expanding Insulation
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Red Devil 0913 Spray Foam & Fill Small Gaps & Cracks Expanding Insulation, Polyurethane Sealant, 12 oz, Off-White, Pack of 1
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Great Stuff Gaps and Cracks Insulating Foam Sealant,12 Ounce - Case of 12
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Tyvek Suit Insulation Installation
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How this calculator works
- Board feet = area × thickness in inches × (1 + waste %)
- R-value = R-per-inch × thickness
- Kits = board feet ÷ kit rating, rounded up
Frequently asked questions
Open-cell or closed-cell spray foam?
Closed-cell gives about R-6.5 per inch, adds structural rigidity and blocks vapor — best for rim joists, crawlspaces and thin cavities. Open-cell is about R-3.7 per inch, much cheaper, and fine for interior walls and attics with room to spare.
Are DIY spray foam kits worth it?
For under about 600 board feet, yes. Past that, contractor pricing per board foot usually beats kit pricing and you get proper ratio control and cleanup.
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Board feet required
1,980 bd ft