Closed cell spray foam costs about $5.60 per square foot installed at 3 inches thick: $1.00 to $1.50 per board foot for the foam plus $0.44 to $3.30 per square foot for the installer. For 1,000 sq ft that is about $5,600, with a range of $3,450 to $7,800. Open cell costs less per board foot, $0.44 to $0.65, but is usually sprayed thicker.
How the spray foam insulation cost is calculated
Foam is priced by the board foot (one square foot, one inch thick), and the crew's time by the square foot sprayed:
Cost = area × thickness × foam price per board foot + area × labor per sq ft, scaled to your state
Foam prices per board foot come from Fixr (open cell $0.44 to $0.65, closed cell $1.00 to $1.50), and Today's Homeowner quotes the same ranges. Labor comes from HomeAdvisor's June 2026 guide: $0.44 to $3.30 per square foot. The typical price is the middle of each range.
Worked example (the default)
- 1,000 sq ft × 3 in = 3,000 board feet of closed cell foam, about R-18.6 at R-6.2 per inch
- Foam: 3,000 × $1.25 = $3,750
- Labor: 1,000 × $1.87 = $1,870
- Typical $5,620, shown as $5,600; low $3,440 (shown as $3,450), high $7,800
Fixr's installed range for new construction is $2.75 to $6.50 per square foot, and the example's $5.62 sits inside it.
Open cell vs closed cell cost
| Foam, 1,000 sq ft | Thickness | Board feet | R-value | Typical cost, before rounding |
|---|---|---|---|---|
| Open cell | 3½ in (2x4 wall) | 3,500 | R-12.6 | $3,780 |
| Open cell | 5½ in (2x6 wall) | 5,500 | R-19.8 | $4,870 |
| Closed cell | 2 in | 2,000 | R-12.4 | $4,370 |
| Closed cell | 3 in | 3,000 | R-18.6 | $5,620 |
R per inch: open cell about 3.6 (DOE), closed cell 6.2 (DuPont Froth-Pak). Per R-value, the two land closer together than per board foot: 2 in of closed cell and 3½ in of open cell give about the same R-12.5, and the closed cell costs about $590 more here.
Per board foot, per square foot
Contractors quote both ways. Per board foot is the foam; per square foot is foam at a set thickness plus labor. HomeAdvisor gives installed prices per board foot of $0.60 to $1.60 for open cell and $1.30 to $3.10 for closed cell. At 3 in, the example works out to $1.87 per board foot, inside that closed cell range.
Existing homes and removal
Spraying into a finished house costs more: Fixr puts existing homes at $3.15 to $7.50 per square foot installed against $2.75 to $6.50 for new construction. "Existing home" raises the labor line by that ratio (3.15 ÷ 2.75, about 15%). Removing old insulation first adds $1.50 to $3.00 per square foot (Fixr).
DIY kits
Turn on "I'll spray it myself" and the calculator prices the foam as DIY kits instead: Froth-Pak kit listings at two distributors work out to about $1.51 to $2.42 per board foot, the small 200 kit being the dearest per board foot. The default job would take 3,000 board feet, 3,000 × $1.67 = $5,010 typical in kits, without paying a crew but also without their equipment. The kits are closed cell, so DIY is only offered for closed cell. Count the kits for your area with the spray foam calculator.
Your state
Choose your state and labor and materials are scaled by regional factors; the choice carries over to the other cost calculators.
Next steps
Check what R-value your climate zone calls for with the insulation calculator; for an attic floor, compare the bag count of loose-fill with the blown in insulation calculator. If the walls get new board afterwards, price it with the drywall installation cost calculator. All cost tools are in project costs, and insulation tools in drywall, paint and walls.