Spray Foam Calculator

Board feet of spray foam from area and thickness.

Area to spray

sq ft

Spray thickness

inches

Foam type

Waste/overspray factor

Tab to move between fields

Board feet needed

1,650 bd ft

R-value achieved

11.1

Foam weight69 lbs

DIY material cost$743.00

Professional install cost$1,073.00

DIY kits (200 bd ft each)9

Acts as vapor barrierNo

How to Use This Calculator

Enter Area to spray, Spray thickness, and Foam type.
Set Open-cell (R-3.7/in, lighter, cheaper), Closed-cell (R-6.5/in, vapor barrier, structural), and Waste/overspray factor.
Review Board feet needed (bd ft) and R-value achieved.
Use Foam weight (lbs) and DIY material cost ($) to inform your decision.

How the result changes with Area to spray

Area to spray: Total surface area to be sprayed (walls, ceiling, rim joist, etc.).
Spray thickness: Desired thickness. Open-cell typically 3-5.5". Closed-cell typically 1-3".
Foam type: Open-cell is cost-effective for interior; closed-cell adds structural strength and moisture resistance.
Waste/overspray factor: Typical waste from overspray, trimming, and irregular surfaces. 10-15% is standard.

Board feet needed: Total board feet of spray foam including waste. 1 board foot = 1 sq ft × 1 inch thick.
R-value achieved: Total thermal resistance at specified thickness.
Foam weight: Weight of cured foam (important for ceiling applications).
DIY material cost: Cost of foam kits for DIY installation.
Professional install cost: Estimated total cost with professional spray foam contractor.
DIY kits (200 bd ft each): Number of 200 board-foot DIY spray foam kits needed.
Acts as vapor barrier: Closed-cell at 2"+ thickness qualifies as a Class II vapor retarder.

Identify Input Parameters
4 parameters
Area to spray = 500, Spray thickness = 3, Foam type = 0, Waste/overspray factor = 10 = 4 input(s) provided
Calculate Board feet needed
Board feet needed = boardFeet * (1 + wasteFactor / 100)
1650 = 1650
Calculate R-value achieved
R-value achieved = rPerInch * thickness
11.1 = 11.1
Calculate Foam weight
Foam weight = volumeWithWaste * densityLbPerCuFt
69 = 69
Calculate DIY material cost
DIY material cost = boardFeetWithWaste * costPerBoardFt
743 = $743