Drywall Sheet Calculator
Calculates standard gypsum drywall panels (1/2" for walls, 5/8" Type X for ceilings/garages) across 4x8, 4x10, and 4x12 foot sheets with perimeter door and window openings deducted.
Formula
Wall Area = 2 × (L + W) × Height - Openings; Sheets = Ceil(Total Sq Ft with Waste ÷ Sheet Sq Ft)
1. Wall Gross Area = 2 × (Length + Width) × Ceiling Height 2. Openings Deduction = (Doors × 21 sq ft) + (Windows × 15 sq ft) 3. Ceiling Area = (Include Ceiling ? Length × Width : 0) 4. Net Drywall Area = (Wall Gross - Deductions) + Ceiling Area 5. Total Area with Waste = Net Area × (1 + Waste %) 6. Sheet Count = Ceil(Total Area with Waste ÷ Sheet Sq Ft)
Inputs
- Room Length
- Room Width
- Ceiling Height
- Drywall Sheet Dimensions
- Drywall Ceiling?
- Number of Doors
- Number of Windows
Worked example
Hanging drywall on 4 walls and ceiling with 2 doors and 2 windows.
Outcome: Gross wall area is 448 sq ft. Deducting openings (-72 sq ft) leaves 376 sq ft. Adding 192 sq ft ceiling equals 568 sq ft net. With 10% cut waste (625 sq ft total), order 20 sheets of 4x8 drywall (640 sq ft total).
Why do drywall professionals prefer 12-foot sheets over 8-foot sheets?
12-foot drywall sheets span entire 12-ft rooms in a single continuous board, eliminating butt joints (where two non-tapered board ends meet). Butt joints require extensive feathering with joint compound to disguise.