Drywall Calculator
Finishing a basement, hanging sheetrock in a garage, or building a new partition wall? Our drywall calculator computes exact sheet counts for 4x8, 4x10, and 4x12 panels, plus estimates required drywall screws, joint tape, and gallons of joint compound.
Project Inputs
Enter your measurements to calculate exact materials
Enter measurements above to view calculation results.
Step-by-Step Calculation Example
Scenario: Hanging 4x8 drywall in a 12 ft × 16 ft room with 8 ft ceilings, 1 door, 2 windows, and drywall on ceiling.
Wall Area: 2 × (16 + 12) × 8 = 448 sq ft gross.
Deduct Openings: 1 door (20 sq ft) + 2 windows (30 sq ft) = 50 sq ft deduction -> 398 sq ft net wall.
Ceiling Area: 16 × 12 = 192 sq ft.
Total Surface: 398 + 192 = 590 sq ft.
Add 10% Waste: 590 × 1.10 = 649 sq ft.
Calculate Sheets: 649 ÷ 32 sq ft per sheet = 20.28 -> 21 sheets.
Drywall Panel Formula
Total Sheets = ⌈ (Net Wall Area + Ceiling Area) × (1 + Waste %) ÷ Sheet Area ⌉ Net wall area is calculated from perimeter times ceiling height minus door and window cutouts. Adding optional ceiling area yields total surface area. Factoring in a 10% waste buffer and dividing by panel size (32 sq ft for 4x8) yields total sheets.
Formula Variables
Calculation Assumptions
- Standard 4x8 sheet covers 32 sq ft.
- Approximately 32 coarse-thread drywall screws (1-1/4") are required per 4x8 sheet.
- Approximately 0.05 gallons of joint compound is needed per square foot across taping and 3 finish coats.
Frequently Asked Questions
Common homeowner and DIY questionsDrywall Calculator
Should I hang drywall vertically or horizontally?
In residential construction, hanging drywall horizontally (perpendicular to wall studs) is recommended. It creates fewer seams to tape and finishes flatter across stud variations.
What thickness drywall should I use?
1/2-inch drywall is the standard for interior residential walls and 16-inch on-center ceiling joists. 5/8-inch Type X fire-rated drywall is required by building code for attached garages and firewall partitions.
How many drywall screws do I need per sheet?
Plan for approximately 32 screws per 4x8 sheet. Screws should be spaced 12 inches apart on ceilings and 16 inches apart on vertical wall studs.
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