Drywall Calculator
Calculate drywall board counts for walls and ceilings, deducting doors and windows with standard sheet sizes.
Last verified: September 2026Inputs & Parameters
Calculation Results
Sheet count is rounded up to whole panels. Includes 10% waste for cuts and corner joints.
Estimating Drywall Sheets, Joint Compound, and Fasteners
Drywall installations require coordinating gypsum board sheet counts (commonly 4x8 ft or 4x12 ft) alongside joint compound (mud), drywall tape rolls, and framing screws. Accurately sizing materials prevents excessive joints and speeds up interior finishing.
Core Mathematical Formulas
- Total Room Surface Area:
Walls Area (Perimeter × Height) + Ceiling Area (Length × Width) - Net Wall Area:
Gross Wall Area - Doors (20 sq ft) - Windows (15 sq ft) - Drywall Sheets:
Sheets = CEILING(Total Area × (1 + Waste%) / Sheet Area (32 or 48 sq ft)) - Planning Compound Rate:
~0.053 gal / sq ft (~1 ready-mix bucket per 900 sq ft)
Worked Example
A 16 ft by 12 ft room with 9 ft ceilings, 2 doors, 2 windows, and ceiling drywall included, using 4x8 ft sheets (32 sq ft) with 10% waste:
1. Gross Walls = 2 × (16 + 12) × 9 = 504 sq ft. Openings Deductions = (2×20) + (2×15) = 70 sq ft. Net Walls = 434 sq ft.
2. Ceiling Area = 16 × 12 = 192 sq ft. Total Area = 434 + 192 = 626 sq ft
3. Drywall Sheets (4x8) = CEILING((626 × 1.10) / 32) = 22 sheets
4. Joint compound and screw figures are approximate planning estimates based on standard residential installation ratios.
Assumptions & Limitations
Panel counts round up to whole sheets. Joint compound, tape, and screw estimates are approximate planning guidelines; actual site consumption depends on framing straightness, joint finishing levels (Level 3 vs Level 5), and cut layouts.