Plasterboard sizes and coverage explained

Calculate the surface first

For a simple wall, area = width × height. For a ceiling, area = room length × room width. When a project contains several walls, calculate each separately and add them. This keeps openings and unusual sections visible.

Sheet coverage examples

A 1.2 m × 2.4 m sheet covers 2.88 m². A 1.2 m × 3.0 m sheet covers 3.60 m². Those are geometric areas; the most efficient sheet size depends on the layout.

The table rounds up whole sheets but does not model where joints or offcuts fall. A layout can require more material even when total sheet area appears sufficient.

Worked wall example

A wall 4.8 m wide × 2.4 m high is 11.52 m². Four 1.2 × 2.4 m sheets also total 11.52 m², so the geometry aligns neatly in this simplified example. Change the wall to 5.0 m wide and cuts become unavoidable even though the area changes only slightly.

Why orientation matters

Two layouts with the same total area can create different offcuts and joint positions. Treat the area calculation as a starting point, then sketch the sheet arrangement for rooms with short returns, sloping ceilings or many openings.

Doors and windows

For a rough estimate you can subtract large openings, but don't assume every removed square metre produces an equal saving in whole sheets. Material around the opening still has to be cut from usable boards.

A useful ordering check

• Measure each surface separately.
• Confirm the actual sheet size you intend to buy.
• Round theoretical sheet counts upward.
• Consider the cut layout before reducing quantities for openings.
• Keep any waste allowance visible rather than burying it in the formula.