How the math works
Perimeter: 2 × (12 + 12) = 48 ftWall area: 48 × 8 ft = 384 sq ftCeiling: 12 × 12 = 144 sq ftTotal × 1.10 waste = 580.8 sq ft4x8 sheets: ÷ 32 = 19; 4x12 sheets: ÷ 48 = 13
Don’t subtract doors and windows on small rooms — the cut-offs rarely get reused. On big rooms subtract openings over 50 sq ft.
Trade pro tips
- Hang the ceiling first, then walls top row first so the factory edge meets the ceiling.
- Use 1/2" on walls; 5/8" or 1/2" ceiling board on ceilings framed 24" OC.
- Stagger end joints and keep them off door and window corners.
Frequently asked questions
How many sheets of drywall for a 12x12 room?
19 sheets of 4x8 for walls and ceiling with 8' walls (14 for walls only), including 10% waste.
How many 4x12 drywall sheets for a 12x12 room?
13 sheets of 4x12 for walls and ceiling — fewer seams to tape than 19 4x8s.
How much mud and tape for a 12x12 room?
About 196 ft of paper tape and 2 × 4.5-gallon buckets of all-purpose compound for three coats.
How many drywall screws for a 12x12 room?
Roughly 528 1-1/4" screws (about one per sq ft at 16" OC framing) — a 5 lb box is plenty.