Calculate plasterboard sheets needed for your room walls
Plasterboard (also known as drywall or gypsum board) is the standard wall lining material in UK construction. Whether you are dry-lining a new-build, renovating a period property, or creating a stud partition wall, knowing exactly how many sheets to order prevents costly over-ordering and the inconvenience of running short mid-project. This drywall calculator works out the number of standard UK plasterboard sheets (2400x1200mm) needed to line the walls of a room. It calculates the total wall area from your room dimensions, subtracts standard openings for doors and windows, and adds a sensible waste allowance to account for cutting, breakages, and off-cuts that are too small to reuse. The calculator uses standard UK opening sizes: 762x1981mm for an internal door (the most common size in UK homes) and 1200x1200mm for a standard window. For non-standard openings, the estimates will be close enough for ordering purposes -- the waste allowance covers minor variations.
To calculate plasterboard sheets for a room: 1. Measure and enter the room length in metres. Measure at floor level from wall to wall. 2. Measure and enter the room width in metres. Again, measure at floor level for accuracy. 3. Enter the ceiling height. The UK standard is 2.4 metres for modern builds. Older properties may have ceiling heights of 2.6-3.0 metres or more. 4. Enter the number of doors in the room. Each standard internal door opening is calculated as approximately 1.98 m2. 5. Enter the number of windows. Each standard window opening is calculated as approximately 1.44 m2. 6. Review the results. The calculator shows gross wall area, net area after subtracting openings, and the number of sheets needed with a built-in 10% waste allowance. For rooms with many alcoves or irregular shapes, consider adding an extra sheet or two beyond the calculated figure.
The drywall calculation uses room dimensions to find the total wall perimeter and area: Perimeter = 2 x (Room Length + Room Width) Gross Wall Area = Perimeter x Ceiling Height For a 4m x 3m room with 2.4m ceilings: perimeter = 2 x (4 + 3) = 14m, wall area = 14 x 2.4 = 33.6 m2. Openings are subtracted using standard UK sizes: - Door: 762mm x 1981mm = approximately 1.98 m2 per door - Window: 1200mm x 1200mm = approximately 1.44 m2 per window Net Area = Gross Wall Area - (Doors x 1.98) - (Windows x 1.44) For 1 door and 1 window: net area = 33.6 - 1.98 - 1.44 = 30.18 m2. Sheets Needed = ceiling(Net Area / 2.88), where 2.88 m2 is the area of a standard 2400x1200mm sheet. Sheets with Waste = ceiling(Sheets Needed x 1.10) The 10% waste factor accounts for cutting around openings, corners, and sockets, as well as any damaged boards.
Standard UK plasterboard is 12.5mm thick and complies with BS EN 520. For areas requiring enhanced fire resistance (such as garage walls adjoining habitable rooms), use 12.5mm fireline board or double-layer 9.5mm boards as specified in Approved Document B. Moisture-resistant board should be used in bathrooms and kitchens. When boarding, always start from a corner and work outwards, staggering joints between courses. Fix boards with 32mm or 38mm drywall screws at 150mm centres along studs or battens. All joints should be taped and filled with jointing compound before skim plastering or direct decoration.