40 m² of wall takes 15 sheets of 4 × 8 ft or 10 sheets of 4 × 12 ft; 400 sq ft takes 14 sheets of 4 × 8 ft.
- 4 × 8 ft sheets
- 4 × 12 ft sheets
| Wall area (m²) | 4 × 8 ft sheets | 4 × 12 ft sheets |
|---|---|---|
| 10 | 4 | 3 |
| 20 | 8 | 5 |
| 30 | 12 | 8 |
| 40 | 15 | 10 |
| 50 | 19 | 13 |
| 60 | 23 | 15 |
| 80 | 30 | 20 |
| 100 | 38 | 25 |
| 120 | 45 | 30 |
| 150 | 56 | 38 |
How it is computed
Sheets = area ÷ sheet area × 1.10, rounded up. A 4 × 8 ft sheet covers 32 sq ft (2.97 m²), a 4 × 12 ft sheet 48 sq ft (4.46 m²). The 10% covers cuts around doors, windows and corners.
FAQ
Should I subtract doors and windows?+
Subtract large openings such as patio doors; for ordinary doors and windows the offcuts rarely get reused, so many installers leave them in.
Are 4×12 sheets worth it?+
They leave fewer joints to tape on long walls and ceilings, but they are heavy and hard to carry up stairs.