Drywall & Plasterboard Calculator
Count the plasterboard (drywall) sheets a wall or ceiling needs from its area and the sheet size, with a waste allowance and the screws.
How many sheets of plasterboard, and how many screws.
How the drywall & plasterboard calculator works
Sheets needed = area to cover ÷ sheet area, plus a waste allowance for cuts around openings and services (10% is usual). Standard sheets are 1200 × 2400 mm (2.88 m²) and 1200 × 3000 mm in metric markets, 4 × 8 ft and 4 × 12 ft in the US. Screws run about 30–35 per sheet at 300 mm centres on walls.
Enter the total wall length and height; ceilings can be entered as one "wall" of ceiling length × width.
Formula: sheets = area × (1 + waste) ÷ sheet area
Worked examples
| Inputs | Sheets to buy | Note |
|---|---|---|
| 20 m of 2.4 m wall, 1200 × 2400 sheets | 19 | 19 sheets |
| 20 m of 2.4 m wall, 1200 × 3000 sheets | 15 | 15 sheets |
| 66 ft of 8 ft wall, 4 × 8 sheets | 19 | 19 sheets |
FAQFrequently asked questions
Which sheet size should I use?
The one that matches your stud height with the fewest joints — 2400 mm sheets stand vertically on 2.4 m walls; 3000 mm sheets laid horizontally suit taller rooms. In the US, 4 × 12 sheets on 8 ft walls laid horizontally minimise joints.
How many screws per sheet?
About 32 for walls at 300 mm centres, 40–50 for ceilings at 200–250 mm centres. Buy 10% extra.
Do I subtract doors and windows?
Small openings, no — the offcut is rarely reusable. Subtract large openings such as garage doors or glazed walls.
What thickness should I use?
10 mm (⅜ in) is common for walls, 13 mm (½ in) for ceilings and where fire or sound rating matters. Codes and manufacturers specify.
Where these figures come from
- The Engineering ToolBox — material densities, coverage and unit data — bulk densities, concrete at 2,400 kg/m³, board and sheet sizes
- Brick Development Association — brick sizes and quantities — 215 × 102.5 × 65 mm, 60 bricks per m²
- UK Government — Approved Documents (Building Regulations) — Building Regulations guidance
Last checked: September 2026. Coverage rates and material sizes are typical manufacturer figures — check the product you buy.