Sheets, joint compound, screws, and cost
Enter your total wall and ceiling area (or compute it as length × height for each surface, minus large openings), pick a sheet size, and this tool estimates how many sheets to buy, how many pounds of joint compound ("mud") and how many screws the job will take, plus a materials cost estimate. A 10% waste factor covers cuts, breaks, and odd-size scraps.
A 12 ft × 12 ft room with 8 ft ceilings: 4 walls × (12 × 8) = 384 ft². With 10% waste: 422 ft². Using 4×8 sheets (32 ft² each): ceil(422 ÷ 32) = 14 sheets. Joint compound: 384 × 0.05 ≈ 19 lb (one 20 lb box of setting compound or 2 buckets of premixed). Screws: ~384, so buy a 1 lb box (≈300 screws) plus a backup — get 500.
4x8 or 4x12 sheets? 4×12 sheets mean fewer seams and faster finishing on long runs, but they're heavy (two-person hang) and harder to transport. For DIY, 4×8 is usually the practical choice.
How much mud per sheet? Budget roughly 1.5–2 lb of joint compound per 4×8 sheet for tape, fill, and skim coats.
How many screws per 4x8 sheet? About 32–36 screws per sheet at 12" spacing — roughly one screw per square foot overall.
Should I subtract doors and windows? Yes for accuracy, but many pros keep them in as natural waste allowance. Our 10% default covers either approach.