Free OnlineCalculators & Converters
Insulation Calculator
Calculate insulation thickness and quantity needed to reach any R-value. Supports fiberglass batts, blown insulation, spray foam, and rigid foam.
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Key Features — Insulation Calculator
6 insulation types with R-value per inch
R-value presets R-13 through R-60
Thickness needed in inches
Bags or rolls to buy
5% waste included
Why Use This Tool — Insulation Calculator
Free Online Insulation calculatorR value calculator — for EveryoneFast & Easy How much insulation do i needBlown insulation calculator — 100% FreeFree Online Attic insulation calculator
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Works Everywhere
Use on any device — desktop, tablet, or phone. No downloads or plugins needed.
Frequently Asked Questions — Insulation Calculator
What R-value do I need?
DOE recommendations: Attic Zone 1-2: R-30 to R-60; Zone 3-4: R-38 to R-60; Zone 5-8: R-49 to R-60. Walls: R-13 to R-21.
What is R-value?
Thermal resistance — higher = better insulation. R-values are additive across layers.
Bags of blown insulation?
Each bag is labeled with coverage charts. This calculator uses adjustable coverage per bag to match your product.