How the panel count is worked out
One panel covers its length times its width. A 2.4 by 0.6 metre panel is 1.44 square metres.
The wall area, plus the waste allowance, is divided by the panel area and rounded up. Twelve square metres with 10 per cent waste is 13.2 square metres, which is 10 panels.
Waste is higher than the area suggests because panels are cut around openings, sockets and the ceiling line, and an offcut rarely fits anywhere else.
Worked example
Twelve square metres of wall with 2.4 by 0.6 metre panels and 10 per cent waste needs 10 panels.
The same wall in 1.2 by 0.6 metre panels needs 19, because each panel covers less and there are more cuts.
Layout, fixing and what is excluded
Where the joints fall is a design decision, not an arithmetic one. Centring a panel on the wall, or starting from a corner, changes how many cuts you make and how much you waste.
Panels are fixed to battens or straight to the wall with adhesive, depending on the product and the substrate. Neither is included here.
A slatted or fluted panel is usually sold with a stated coverage per pack, which already accounts for the gaps, so use that figure instead of the area.
Limits of this calculator
It assumes flat panels on a flat wall. A wall out of plumb needs battens to straighten it, which is a separate job.
It does not account for a panel that has to be cut around a window or a door, beyond the waste allowance.
It does not include adhesive, battens, trims or the cost.
For a plastered finish instead, use the plasterboard calculator.
Inputs for the panelling calculator
Wall area
Total wall area to panel, less the doors and windows you are not covering.
Panel length
Length of one panel or board, 2.4 m for a standard sheet.
Panel width
Width of one panel, 0.6 m for a standard board.
Waste allowance
Extra for cuts around openings and at the ceiling. Ten per cent is normal.
CALCULATOR QUESTIONS
Panelling calculator questions
How many panels for a wall?
Twelve square metres takes 10 panels of 2.4 by 0.6 metres with 10 per cent waste.
Should I add more waste?
Yes for a wall with several sockets or a window, where every cut leaves an unusable offcut.
Do slatted panels work the same way?
No. Slatted systems quote a coverage per pack that already allows for the gaps.
Are battens included?
No. Battens, adhesive and trims are separate.