Plasterboard Calculator UK
Work out exactly how many plasterboard sheets you need for walls and ceilings, with openings, extra layers and a wastage allowance built in.
Calculate Plasterboard Sheets
Enter the size of the wall or ceiling, pick your board size, and get the number of sheets to order. For a whole room, run each different surface and add the results.
Plasterboard Quantity Calculator
Get an instant sheet count with a safe cutting allowance.
Understanding Plasterboard Quantities
Key points for accurate ordering and less waste
Measure Each Surface
Work out length × height for each wall and length × width for the ceiling. Run the calculator once per different surface and add the totals.
Deduct Big Openings
Subtract full-size doors and large windows. Leave out sockets, switches and small gaps, as your wastage allowance already covers them.
Allow for Wastage
Cuts around corners and openings create offcuts. A 10% allowance suits most rooms, and more is sensible for complex layouts.
Round Up to Whole Sheets
Boards are sold whole, so the final figure is always rounded up. Double-layer jobs need twice the area, which the layers option handles.
Plasterboard Sizes & Coverage Guide
Common UK sheet sizes, the area each one covers, and how many you would need for 10 m² of single-layer boarding with a 10% wastage allowance.
| Sheet Size | Coverage per Sheet | Sheets for 10 m² (incl. 10%) | Typical Use |
|---|---|---|---|
| 1800 × 900 mm | 1.62 m² | 7 | Easy handling, stairs, small rooms |
| 2400 × 900 mm | 2.16 m² | 6 | Walls, tight access |
| 2400 × 1200 mm | 2.88 m² | 4 | Standard walls and ceilings |
| 2700 × 1200 mm | 3.24 m² | 4 | Taller walls, fewer joints |
| 3000 × 1200 mm | 3.60 m² | 4 | High walls, large ceilings |
Plasterboard Calculator FAQ
Answers to the most frequently asked questions about measuring and ordering plasterboard.
Multiply the length by the height (or width for a ceiling) to get the area in square metres, subtract large openings such as doors and windows, then divide by the area of one sheet. A standard 2400 x 1200 mm sheet covers 2.88 m². Add 10% for wastage and round up to the next whole sheet.
The most common UK sheet is 2400 x 1200 mm, covering 2.88 m². Other sizes include 1800 x 900 mm for easier handling, plus 2700 x 1200 mm and 3000 x 1200 mm for taller walls and fewer joints.
10% is a typical allowance for a simple room. Use 12 to 15% for rooms with many openings, alcoves or awkward cuts, and when working with smaller boards, as more cuts mean more offcuts.
Subtract large openings such as full-size doors and big windows. Small openings like sockets and switches can be ignored, since the wastage allowance covers them. If an opening is less than about one square metre, many fitters leave it in the total.
12.5 mm is the standard for most walls and ceilings. 9.5 mm suits lighter jobs and overboarding, while 15 mm gives extra strength, sound and fire performance. Always follow the board manufacturer’s guidance on fixing centres and framing spacing.