Insulation Calculator

Estimate how many bags of batt or blown insulation, or rigid foam sheets, you need for a target R-value. Includes waste and material cost.

Enter total area directly

Total area to insulate (sq ft)Waste / overage (%)

Insulation typeTarget R-valueApprox. installed thickness (in)Coverage per bag/sheet (sq ft)Price per bag or sheet

Units needed

20.57 exact (rounded up)

Total estimated cost

$1,008

at $48 each

Area: 800 sq ft
Area with waste: 864 sq ft
Coverage per unit: 42 sq ft
Units (bags/sheets): 21

Coverage varies dramatically by product, R-value, and installed depth. Blown cellulose is dense and efficient; batts depend on width (15" vs 23") and compression. Rigid sheets are 32 sq ft each. Always check the bag or bundle label for the exact R and coverage at your depth.

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