Insulation Calculator
Calculate insulation for walls, attics, and floors. Get rolls/batts for fiberglass or bags for blown-in cellulose based on area and R-value.
๐งค Insulation Calculator
Results
Total Area320.00 sq ft
Rolls / Batts8 rolls
๐ก How to Calculate Insulation Needs
Insulation is sized to fit between standard framing. Batt insulation for 2ร4 walls (R-13) comes in rolls covering approximately 40 sq ft. For 2ร6 walls (R-19), coverage is about 48 sq ft per roll. Attic insulation (R-30 to R-38) has lower coverage per roll due to greater thickness.
Blown-in cellulose insulation is sold in bags, with each bag covering roughly 40 sq ft at R-13 depth. It's ideal for attics and retrofitting existing walls. For attics, the recommended R-value is R-38 to R-49 in most US climate zones.
A 40ร8 ft wall = 320 sq ft. With R-13 batt insulation (40 sq ft/roll) = 8 rolls. For blown-in cellulose = 8 bags. Attic: same area at R-38 needs about 10 rolls or 13 bags.