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How many plasterboard sheets for a 3×5 m room with a 2.4 m ceiling?
You'll need 15 sheets of standard 1200×2400 mm plasterboard to line the walls of this room, including a 10% cutting waste allowance.
A standard 2400 mm sheet matches this ceiling height, so it runs vertically wall-to-ceiling in one piece with no horizontal joins needed.
| Room size | 3 m × 5 m |
|---|---|
| Ceiling height | 2.4 m |
| Wall perimeter | 16 m |
| Wall area (perimeter × height) | 38.4 m² |
| Waste allowance | 10% |
| Area incl. waste | 42.24 m² |
| Sheet size | 1200 mm × 2400 mm (2.88 m² each) |
| Sheets needed | 15 |
Assumptions
- Standard sheet size 1200 × 2400 mm (2.88 m²), the /site/materials calculator default.
- 10% cutting waste allowance.
- Wall area only — perimeter × ceiling height. The ceiling lining and any door/window openings are not deducted, so the true count on a room with large openings will be a little lower.
Check before you order: Confirm the sheet size your supplier actually stocks (1200×2400/2700/3000 mm and 1350 mm-wide sheets all exist) and the wastage allowance with your plasterer before ordering — this figure doesn't deduct door or window openings.
How this is worked out & FAQ
How this is worked out
- Work out the wall perimeter: 2 × (length + width).
- Multiply the perimeter by the ceiling height to get wall area.
- Add the waste allowance, then divide by the sheet area and round up.
FAQ
Does this include the ceiling?
No — this figure is walls only (perimeter × ceiling height). Add the room's floor area again, divided by 2.88 m² per sheet, if you're also lining the ceiling.
Why not deduct doors and windows?
It keeps the figure a safe over-estimate for ordering. Openings reduce the true area needed, but offcuts from a cut sheet often can't be reused elsewhere, so most estimators order on the full wall area anyway.
What if my ceiling height isn't listed?
Use the calculator directly at /site/materials — enter your own wall area (perimeter × height) and it will work out the sheet count instantly.
Estimates only — allow for laps, cuts and site conditions. ← more plasterboard sheets · All material calculators