Which sheet size is assumed?

2400 by 1200 mm, the common plasterboard sheet.

Does this include waste?

Yes — the percent you set, 10% by default, then rounded up to a whole sheet.

Only if you enter the combined length. Length times height is one face.

How many 2400 × 1200 mm plasterboard sheets a wall needs, with waste.

How many 2400 × 1200 mm plasterboard sheets a wall needs, with waste you can change.

Wall length

Wall height

Waste allowance

Sheets to order

You need 7 sheets of 2400 × 1200 mm for 16.2 m², including 10% waste.

This is one face. Double the length for both sides of a wall.
Openings still need sheets for the cuts around them — waste covers some of that.

Sheets7

Measurements stay in this browser. Nothing is uploaded.

A wall 6 m long and 2.7 m high is 16.2 m². With 10% waste that’s 17.8 m². A 2400 × 1200 mm sheet covers 2.88 m², so you need 7 sheets.

Which sheet size is assumed?: 2400 by 1200 mm, the common plasterboard sheet.
Does this include waste?: Yes — the percent you set, 10% by default, then rounded up to a whole sheet.
Are both sides of a wall included?: Only if you enter the combined length. Length times height is one face.