Wall Area Calculator

How this calculator works

Gross wall area = 2 x (length + width) x height, or length x height for a single wall face when width is 0. Net wall area = gross area - (doors x door area) - (windows x window area). Purchase area = net area x (1 + waste / 100).

Worked example

A 4 m x 3 m room with 2.4 m walls, one door, and two windows has 33.6 m2 gross wall area and 30.9 m2 net, after subtracting openings.

Assumptions to check

The room is rectangular; bay windows, alcoves, and vaulted ceilings need manual adjustment.
Default door and window areas are editable approximations, matching the paint calculator.
This tool returns area only - use paint, wallpaper, drywall/plasterboard, or siding/cladding for a material quantity from this area.

Read the calculation and QA methodology →

FAQ

How is this different from the paint calculator?

Paint converts wall area into liters of paint using coverage and coats. This tool stops at the area itself, so it can feed wallpaper, drywall, and cladding calculations too.

Should I subtract doors and windows?

Yes for an accurate material order - this calculator does it automatically using editable average sizes.

Can I use this for a single wall instead of a full room?

Yes - set the "width" of the other wall to 0 to get a single wall face (length x height), or use the drywall/cladding calculators directly with a single length and height.