Skirting Board Calculator

What Goes Into the Numbers

The calculator starts with the full perimeter of your room — twice the length plus twice the width. From that total, it subtracts the width of each doorway opening, because skirting stops where the door architrave begins. The result is your net skirting length. Skirting is always measured by length, not by floor area, which is why every figure here is in linear metres or whole boards rather than square metres.

A waste factor is then applied to the net length to account for material lost to cutting. Every internal corner needs a cope or mitre cut, and every external corner needs a mitre. These cuts produce short offcuts that are often too small to reuse. The default 10% waste covers a standard rectangular room with four internal corners and one or two doorways.

The final step divides the total length (net length plus waste) by the individual board length you have chosen, then rounds up to a whole number. Standard UK skirting boards come in 2.4m or 3m lengths. Longer boards mean fewer joints along a wall, but they are harder to transport and handle in tight spaces. If you are planning to paint the skirting after fitting, our paint coverage guide explains how to estimate the quantity for trim work.

Making Sense of the Output

Three outputs appear after you press Calculate. Room perimeter is the full circuit of the room before any deductions — this is useful as a sanity check against your tape measure reading. Net skirting length is the perimeter minus all doorway widths, representing the actual length of wall that needs skirting.

Boards needed is the number of whole boards to buy. This figure includes your waste allowance and is always rounded up, because you cannot buy a fraction of a board. In practice, offcuts from one wall often fit a shorter run on another wall, which is why 10% waste is usually sufficient for a simple room. The rounding-up itself also creates a small buffer — if the maths says 6.3 boards, you buy 7, and that extra 0.7 of a board covers most minor miscalculations. The perimeter-based approach is similar to how hedge spacing works outdoors — both divide a linear measurement into fixed-length units.

Choosing the Right Materials

Skirting is sold by length, not by area, so the job comes down to buying enough boards in a length that suits your walls. UK skirting comes in a handful of standard lengths, and the right choice balances fewer joints against easier handling and transport.

• 2.4m: the common length at DIY sheds such as Wickes and B&Q, easy to carry and handy for small rooms and short runs
• 3m (sometimes 3.05m): a popular MDF length that spans most bedroom walls in one or two pieces
• 4.2m: the most widely stocked long MDF length, sold by Howdens, B&Q, Wickes, and the MDF specialists, and ideal for long living-room or hallway walls
• 5.4m: available from specialist MDF suppliers for the longest walls with the fewest joints, though awkward to move and cut

If you already know your total length, converting it into boards is one sum: divide the total by your chosen board length and round up, then add waste. For example, 31m of skirting (about 102 feet) divided by 2.4m boards is 12.95, which rounds to 13 boards; allowing 10% for cutting waste takes you to 14. The calculator above does this for you once you enter the room size and pick a board length.

Most skirting today is fixed with grab adhesive rather than nails alone. Manufacturers quote a 310ml cartridge as roughly 12 to 15 metres of a 5 to 6mm bead, but a board needs more than a single bead to hold. Run a zig-zag of adhesive up the back of each board and one 310ml cartridge fixes around 5 to 6 metres of standard-height skirting, so a typical 14m room takes about three cartridges. Tall period boards use more, short modern boards less, and it is worth buying one spare cartridge so a half-empty tube does not stop the job.

If you are trimming the doorways at the same time, architrave is a separate calculation from the skirting. One architrave set frames a single face of a standard 762 by 1981mm door with two vertical legs and one head, roughly 6m of moulding; both faces of the same doorway need two sets, about 10 to 12m in total. Architrave is sold in the same standard lengths as skirting, so a single 2.4m length yields both legs and the head for one side with little waste. Once the trim is fixed, you can estimate the paint for skirting and architrave together.

Common Mistakes to Avoid

Corner joints are where skirting jobs succeed or fail. Internal corners (where two walls meet inward, like the corner of a bedroom) should always use a cope joint. A coped joint scribes one board to follow the profile of the other, creating an interlocking fit that stays tight even as the house settles and walls move fractionally. Cut the first board square into the corner, then cope the second board to sit over it.

External corners (outward-pointing corners like a chimney breast or pillar) use mitre joints. Cut both boards at exactly 45 degrees with a mitre saw. Test-fit the joint before applying any adhesive. If the corner is not perfectly square (and many are not), you may need to adjust the angle by a degree or two.

Fix skirting boards with a combination of panel adhesive and panel pins. The adhesive carries the weight and bonds the board to the wall, while the panel pins hold the board in position while the adhesive sets. Where the wall has timber studs, drive the pins into the studs, because plaster alone will not hold a pin. On solid masonry walls, let the grab adhesive do the structural work and add the occasional screw and wall plug instead of pins.

Start with the longest wall in the room and work your way around. This approach lets you use the longest boards on the most visible runs, saving shorter offcuts for behind furniture or inside alcoves. At each doorway, cut the skirting square so it sits flush against the architrave. The two profiles, skirting and architrave, should meet cleanly without overlapping.

Profile choice is partly aesthetic and partly practical. Ogee skirting has a traditional S-curved profile common in Victorian and Edwardian homes. Torus has a simpler rounded half-circle. Bullnose is a plain rounded top edge. Pencil round and chamfered profiles suit modern interiors with clean lines. Ornate profiles like ogee require more skill to cope cleanly because the curves must match precisely at the joint. Coordinating skirting with wallpaper above creates a cohesive room finish, so choose a profile height that works with your paper's pattern scale.

When to Adjust These Numbers

Rooms with more than four corners need extra waste allowance. Alcoves, chimney breasts, and bay windows all create additional corners that require mitre or cope cuts. Add roughly 2% waste per extra corner beyond the standard four.

Bay windows with angled walls need custom mitre angles rather than the standard 45 degrees. Measure the actual angle of each bay panel with a sliding bevel gauge and transfer that angle to your mitre saw. A canted (splayed) bay typically has 135-degree internal corners, which need 22.5-degree mitres, though bays vary, so trust the bevel reading over any assumed standard angle.

Hallways with many doors have a high deduction ratio. A hallway with five door openings may only need skirting on 60% of its perimeter. In these cases, check that the calculator's board count still makes sense — you may be able to drop down to shorter boards to reduce waste from long offcuts.

If you are fitting skirting over a floating floor (laminate, vinyl, or engineered wood), the floor needs an 8 to 10mm expansion gap around its perimeter — Quick-Step's fitting spec; some manufacturers allow up to 12mm. Fix the skirting to the wall only so it covers that gap, and never pin or glue the skirting down onto the floor itself, or the floor cannot expand and contract and will buckle. Our laminate flooring estimator accounts for that perimeter gap when calculating board quantities.