How many plasterboard sheets do I need?

Estimate whole plasterboard sheets from net wall area, optional ceiling area, the purchased sheet dimensions, and a cutting allowance.

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ToolDrywall Calculator
Input
Output
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How it works

Room perimeter × height gives four-wall area, measured openings are deducted, and a selected ceiling adds length × width. The cutting allowance increases that total before division by sheet length × sheet width rounds up to complete boards.

Formula
sheets = ceiling(net boarded m² × (1 + waste ÷ 100) ÷ sheet m²)
  • Screw and joint-compound quantities are omitted because British Gypsum uses different fixing centres for partitions, ceilings, ends, angles, and encasements.
  • Sheet size and cutting allowance are required from the selected board and layout rather than fixed at 2.4 × 1.2 m and 5%.

Worked example

A bedroom, walls only
4m by 3m, 2.4m high, one door and one window
Input
											Length m: 4
Width m: 3
Height m: 2.4
Opening area m2: 2.94
Sheet length m: 2.4
Sheet width m: 1.2
Waste percent: 5
Output
												Wall area: 30.66
Ceiling area: 12
Total area: 30.66
Area with waste: 32.19
Sheets needed: 12

When to use this

Metal-stud partitions board framed faces, bedroom linings deduct measured openings, and ceiling takeoffs add the footprint before following their separate fixing schedule.

Edge cases

  • An opening total equal to or larger than all four walls is rejected instead of returning a plausible zero-sheet order.
  • The ceiling contributes no area until selected; when selected, the full room footprint enters before the cutting allowance.
  • Any fractional final board rounds up, even when total unused area across earlier cuts appears large, because this area model does not solve a cutting layout.

References