Drywall / Plasterboard Calculator
Calculate how many plasterboard sheets you need for walls and ceilings. Accounts for openings like doors and windows, plus wastage for cuts.
When to Use
- Domestic wall lining (single or double layer)
- Ceiling installations
- Stud wall construction
- Patching and repair work
Standard Sheet Sizes
| Application | Size | Thickness |
|---|---|---|
| Standard Walls | 1200mm × 2400mm | 12.5mm |
| Ceilings | 1200mm × 2400mm | 9.5mm |
| Tall Ceilings | 1200mm × 2700mm | 12.5mm |
| Heavy Duty | 1200mm × 2400mm | 15mm |
Additional Materials Needed
- Drywall screws: approximately 40 per sheet
- Joint tape: approximately 3 metres per sheet
- Joint compound: approximately 1kg per 3-4 m²
- Corner bead for external corners
Tips
- Allow 10-15% wastage for cutting around openings
- Measure and subtract doors, windows, and large openings
- Plan sheet layout to minimize butt joints
- Stagger joints in double-layer applications
UKUK Building Regulations
References & Sources
Standards Cited
- BS EN 520 — Gypsum plasterboards — Definitions, requirements and test methods
Defines standard plasterboard sizes and thicknesses (9.5mm, 12.5mm, 15mm) used in the calculator - BS 8212 — Code of practice for drylining and partitioning using gypsum plasterboard
Provides guidance on fixing centres, joint treatment, and installation methods for plasterboard - British Gypsum White Book — British Gypsum White Book — Specification and Installation Guide
Industry reference for standard sheet sizes (1200x2400mm, 1200x2700mm, 1200x3000mm) and fixings guidance
Formulas Used
- Wall Area:
wallArea = wallLength x wallHeight
Source: Standard geometry - Net Area:
netArea = wallArea - openingArea
Source: BS 8212 - Sheets Required:
sheets = ceil(netArea / sheetArea)
Source: BS 8212 - Sheet Area:
sheetArea = (sheetWidth / 1000) x (sheetHeight / 1000)
Source: BS EN 520 — Standard sheet: 1200mm x 2400mm = 2.88 m² - Screws per Sheet:
screws = sheetsRequired x fixingsPerSheet x 1.1
Source: British Gypsum White Book — Default 40 fixings per sheet with 10% extra; typical fixing centres 300mm at edges, 300mm in field - Joint Tape:
jointTape = sheetsRequired x 3m
Source: British Gypsum White Book — Approximately 3m of joint tape per standard sheet
Key Assumptions
- Standard plasterboard sheet size is 1200mm x 2400mm (2.88 m²) — BS EN 520 / British Gypsum White Book
- Standard wall board thickness is 12.5mm; ceiling board is 9.5mm — BS EN 520
- Default 40 fixings (screws) per standard sheet at recommended centres — British Gypsum White Book
- Default 10% wastage for cuts and fitting around openings — Industry standard practice