Data checked October 2026

Drywall & Insulation Calculators

Walls and attics are bought by the sheet, the bag and the R-value. These calculators start from the coverage charts drywall and insulation makers publish and the R-values the Department of Energy recommends by climate zone, so you buy the right count the first time.

Blown-In Insulation CalculatorFor R-38 over 1,000 sq ft of bare attic you need about 19 bags of fiberglass (27.5 lb) or 53 bags of cellulose (25 lb). Enter your attic size, climate zone and what's already up there to get bags and blowing depth.Drywall CalculatorDivide the wall and ceiling square footage by the sheet size and add 10%: a 12 × 12 ft room with 8 ft walls, a ceiling, one door and two windows takes 17 sheets of 4×8 drywall, one 4.5-gallon pail of mud and about 260 ft of tape.Insulation Calculator1,000 sq ft of 2×4 wall with studs 16 in on center takes about 99 R-13 batts (15 × 93 in) — 906 sq ft of cavity once the studs are subtracted. Pick your climate zone and the calculator sizes walls, attic floors or floors over a crawlspace.

Keep planning

Other calculators

Area & Volume Concrete & Masonry Lumber, Decks & Stairs Gravel, Sand & Mulch Paint & Stain Flooring Tile Fencing Roofing & Siding Electricity Cost Solar