What are linear metres?

A linear metre is exactly one metre measured along a single straight line. The word "linear" is there to distinguish it from a square metre (m²), which measures area in two dimensions.

In a flooring takeoff, linear metres show up for any product priced or installed by the running metre: skirting boards, scotia, quad, transitions and threshold strips, stair nosings, and broadloom carpet bought from a roll where one dimension is fixed (e.g. a 3.66 m or 4 m wide roll, with run length measured in linear metres).

The most common confusion is between perimeter and linear metres. They are not the same thing. The perimeter of a room is the sum of all wall lengths in linear metres — a 5 m × 4 m rectangular room has a perimeter of 18 linear metres. But the linear metres of skirting you actually quote will be lower than the perimeter, because you subtract door openings.

The other common linear-metres calculation is broadloom carpet ordering. Broadloom is supplied at a fixed roll width (see /glossary/broadloom-roll-width for the AU widths) with the along-the-roll dimension measured in linear metres. Convert either direction — floor area to roll length, or roll length to coverage — with the dedicated /calculators/square-metres-to-linear-metres converter. For a single room, use /calculators/carpet-broadloom. For a whole-house cut across multiple rooms from one roll, use /calculators/carpet-cut-list.

AreaSum reports each room's perimeter in linear metres next to its area in m². For doorways and other gaps where skirting is not installed, drop the excluded segments into the room's notes — the perimeter figure stays accurate, and the trim quantity gets a quick manual deduction at quote time.