How this calculator works
Add up the wall area (the perimeter × the height) and, if you are boarding it, the ceiling (length × width). Add a waste allowance, and divide by the area of one sheet: a standard 2400 × 1200 mm sheet covers 2.88 m². Screws go in at about 300 mm centres, which is about 11 per square metre, and jointing tape is needed along every joint.
Worked example: a 4 × 3 m room with a 2.4 m ceiling has 33.6 m² of walls and 12 m² of ceiling, which is 45.6 m². With 10% waste that is 50.2 m², or 17.4 sheets, so buy 18. They need about 570 screws.
Tips before you buy
- Board the ceiling first, then the walls. A plasterboard lift or a helper is a must for the ceiling.
- Fix the boards with the long edges across the joists or studs, and stagger the joints between neighbouring sheets.
- Use plasterboard screws, not general-purpose screws, and set them just below the surface of the paper without tearing it.
- For a skim finish, use a standard tapered-edge board, or a square-edge board if you are going to skim the whole wall. Decide before you buy.
- Plasterboard is heavy: a standard 2400 × 1200 mm sheet of 12.5 mm board weighs more than 20 kg. Carry it on its edge, and use a plasterboard carrier if you can.
Tools & materials for this project
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Frequently asked questions
How many sheets of plasterboard for a 4m x 3m room?
18 sheets of 2400 × 1200 mm for the walls and ceiling with 10% waste, or 13 for the walls alone.
What size is a standard sheet of plasterboard?
2400 × 1200 mm, which covers 2.88 m². Other common sizes are 1800 × 900 mm and 3000 × 1200 mm.
How many screws for a sheet of plasterboard?
About 30 to 35 for a standard 2400 × 1200 mm sheet, at about 300 mm centres.
What thickness of plasterboard should I use?
12.5 mm for most walls and ceilings, and 15 mm where you need more fire resistance or a stiffer ceiling. Check the Building Regulations for fire-rated walls.
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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.