Skirting Board Calculator

Skirting is bought by length but measured by the running metre of wall, minus the door openings. A 5 × 4 m room is 18 m around; subtract 0.9 m for each door and add 10 % for mitres and corners, and six 2.5 m lengths turn into seven.

Corners consume length. An external mitre loses the width of the board from each piece, and a room with four external corners loses about half a metre that no area calculation will reveal.

Skirting height is a visual decision, but it is also a practical one: tall boards hide an uneven wall-floor junction that short boards expose. In older houses the wall is rarely straight along the floor, and a 120 mm board copes where a 60 mm one needs filling.

The wall behind the board matters for fixing. Plasterboard needs the studs found or a grab adhesive, masonry takes plugs, and a dot-and-dab wall may need longer fixings than the board height suggests.

Skirting is where cables run and where sockets sit, so the board usually has to be cut around boxes rather than simply fixed. Cutting around a socket weakens the piece, and the offcut cannot be used elsewhere, so a room with many sockets needs a longer offcut allowance.

Paint the board before fixing or accept cutting in twice. And keep one spare length: the piece behind the sofa will be damaged by a vacuum cleaner within a year, and the profile will have been discontinued by then.