Baseboard (skirting board) is the simplest material in the house to estimate and still one of the most commonly under-bought, because the number in your head — “the room is about 14 feet” — is one wall, and the material runs on all four, minus only where doors interrupt it. This baseboard calculator adds up the perimeters of as many rooms as you give it, deducts the total width of your door openings, adds a cutting-and-mitre waste allowance, and converts the result into boards of the length your store sells, in feet or metres as you enter them.
Worked example
One room, 4 m × 3 m: perimeter 2 × (4 + 3) = 14 m. Two door openings at 0.9 m each deduct 1.8 m, leaving 12.2 m of wall that actually takes board. Cutting waste at 10% raises the buy figure to 13.42 m; in 2.4 m boards that is ceil(13.42 ÷ 2.4) = 6 boards (14.4 m bought). Run the same room in imperial — 13 ft × 10 ft, two 3 ft doors, 8 ft boards — and the maths is identical: 46 − 6 = 40 ft net, 44 ft with waste, 6 boards. The waste allowance is not pessimism: every external corner is a mitre, every mitre is a chance to cut the mirror image of the piece you needed, and the offcuts from a doorway never quite reach the next wall.
Where baseboard does and does not run
Deduct: door openings (measure the architrave-to-architrave gap the board would have crossed), fitted wardrobes and kitchen units that sit permanently against the wall, and the hearth footprint of a fireplace. Do not deduct: radiators (the board runs behind them, and removing it looks worse than any saving), windows however low, and door frames — the board butts to the architrave, so the opening you deduct is the clear doorway, roughly the door leaf width plus a finger. Built-in bookcases that stop 100 mm short of the floor are a judgement call: board behind them is invisible but protects the wall when they move.
Choosing the waste percentage
Rectangular rooms, long boards, square internal corners: 10% is honest. Rooms with chimney breasts, bay windows and many external corners: 15%. Board sold in short lengths (1.8 m) wastes more than board in 3 m lengths, because every wall longer than one board needs a joint and every joint needs a clean end. If you are matching an existing profile in a renovation, buy 20% over and keep the receipt — profiles are discontinued more often than paint colours, and the garage offcut is tomorrow’s patch repair from the same production run.
Scope
This is a length estimator: it does not choose the board’s height or profile, count corner blocks or adhesive, or allow for the pattern repeat of a pre-finished board. Our Spanish companion does the same job in metres with the rodapié sold by strips. What this one settles — the figure the order is written from — is how much board the walls genuinely consume and how many saleable pieces that means, so the last wall of the last room does not wait a week for one more board.
Measuring rooms that are not rectangles
L-shaped rooms have one correct perimeter and several tempting wrong ones. The reliable method is to walk the walls with the tape and add every straight run the board will follow: the perimeter is the sum of wall faces, not a formula. An L-shape’s two “missing corner” walls count too — the internal corner where the L turns takes board like any other wall. For a room with an alcove or chimney breast, the same walk works: into the alcove, across its back, and out again. Where a wall is interrupted by a wide opening you will not board across — a serving hatch into a kitchen, a open-plan archway — deduct its width exactly like a door. If in doubt whether a run takes board, include it: a spare length in the garage is a future repair, while a missing 400 mm on Saturday afternoon is a second delivery charge.
Related tools
Versión en español: Calculadora de Metros Lineales de Rodapié para Suelo: tiras a comprar por habitación · Paint Calculator · Tile Calculator.
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