Plasterboard calculator
Plasterboard comes in standard sheets, most often 1200 mm wide and 2000–3000 mm long. Turning the area of a wall or ceiling into a number of sheets is simple, as long as you remember the waste from edge cuts and cut-outs.
The calculator works for one layer of boards; a stud partition has boards on both faces.
Your measurements
Result
- Area to order (incl. waste)
- 16.50 m²
- Boards needed
- 6 pcs
One layer of boards. A stud partition has board on both faces, so double the area.
How the calculation works
- Area to board = the area of the wall or ceiling, in m².
- Area to order = area + 10% waste (15% for coffered ceilings or many cut-outs).
- Boards = area to order ÷ area of one board (1.2 × 2.6 m = 3.12 m²), rounded up.
Worked example
For a 15 m² ceiling with 10% waste you order 16.5 m². With 1200 × 2600 mm boards (3.12 m²) you need 16.5 ÷ 3.12 = 5.3, so 6 boards.
What the calculator assumes
- One layer of boards; for a partition wall double the area.
- Standard boards are 12.5 mm thick; moisture-resistant boards are used in bathrooms and fire-rated boards where fire resistance is required.
- The waste covers edge cuts and cut-outs for boxes and downlights.
When to adjust the result
- Metal studs and tracks, screws, joint tape and jointing compound are not included.
- In a partition, mineral wool between the boards improves sound insulation.
- Ceiling profiles are usually spaced 40–50 cm apart; wider spacing can let boards sag over time.
Plasterboard tips
Choose the board for the room: standard boards for dry rooms, moisture-resistant boards for bathrooms and kitchens, fire-rated boards where required, and acoustic boards for quieter walls. Stagger joints between layers and keep them off the corners of door and window openings to reduce cracks.
Screw boards every 20–25 cm on walls (closer on ceilings), with screw heads just below the surface without tearing the paper. Tape and fill joints in several thin coats, and plan heavy fixings — wall cupboards, TVs, sinks — with timber or metal backing before boarding.
Frequently asked questions
How many plasterboard sheets for a 3 × 4 m ceiling?
12 m² plus 10% waste is 13.2 m²; with 1.2 × 2.6 m boards that is 13.2 ÷ 3.12 = 4.2, so 5 boards.
Which plasterboard for a bathroom?
Moisture-resistant boards, combined with a waterproofing system in the areas that get wet (shower, around the bath). Follow the system manufacturer's instructions.
What stud spacing for plasterboard?
Usually 40–60 cm; 60 cm is common for 12.5 mm boards on walls, closer on ceilings or with thinner boards.
How do I hang heavy items on plasterboard?
Use backing timber or metal installed before boarding, or cavity fixings rated for the weight.