Baseboard Calculator
Corners consume length the tape measure does not show.
Work out Baseboard. Corners consume length the tape measure does not show. States the assumption instead of hiding it.
17.1 m of length needed
8 lengths
19.2 m bought · 2.1 m offcut
Mitred internal and external corners each consume length beyond the wall measurement, and a mitre cut wrong is a wasted piece rather than a shortened one. The waste allowance should be higher for a room with many corners than for a plain rectangle. Buying a length longer than the longest wall avoids a join in the most visible run, which is usually worth the extra cost.
How the Baseboard Calculator works
Skirting or baseboard for a room perimeter, less doorways, rounded up to whole lengths with the offcut stated. Mitred corners consume length beyond the wall measurement, which is why the waste allowance matters.
Also known as: skirting board calculator · how much skirting do i need · baseboard linear feet calculator · skirting for a room perimeter
Corners consume length the tape does not show
A mitred corner cuts material away from both pieces, and a mitre cut wrong is a wasted piece rather than a shortened one. That is what the waste allowance actually covers — not offcuts, but errors and the geometry of corners.
So the allowance should scale with corner count rather than with area. A plain rectangular room needs ten percent; a room with a chimney breast, an alcove and a bay needs considerably more, because it has three times the corners in the same perimeter.
Buying a length longer than the longest wall is worth the cost where it is available. A join in the middle of a long visible wall is the most obvious flaw in a skirting installation, and a single length removes it entirely.
Mitre against scribe
A mitre cuts both pieces at 45 degrees to meet at a corner. It works perfectly when the corner is square, which very few corners in a real building are — and a mitre cut to the assumption leaves a visible wedge-shaped gap.
A scribed joint cuts one piece square into the corner and shapes the second to the profile of the first with a coping saw. It handles out-of-square corners far better and, critically, does not open up as the timber shrinks — the profile stays in contact.
Where a mitre is used, measuring the actual corner angle and halving it is the fix. Few rooms are square, and the difference between a true 45 and the correct half-angle is exactly the gap that shows.
Sequence, fixing and filling
Skirting goes on before carpet and after most hard flooring, so it can cover the expansion gap a floating floor needs. Carpet is fitted afterwards and tucked under the skirting edge, which is why fitting skirting on top of carpet makes replacement difficult later.
Fixing depends on the wall. Adhesive alone works on a flat wall and struggles on an uneven one, where mechanical fixings are needed to pull it in. On a masonry wall that usually means screws into plugs.
The gap above the skirting is filled with flexible decorator's caulk rather than rigid filler. The wall and the timber move relative to each other seasonally, and rigid filler cracks along that line within a year.
Where to go next
The Baseboard question rarely arrives on its own. These are the ones that usually come with it:
- Trim and Molding Calculator — Pattern matching adds waste beyond the percentage.
- Carpet Calculator — Roll width decides the waste, not the area.
- Floor Tile Calculator — Buy a spare box — dye lots do not match later.
- Ring Size Calculator — Finger measurement to US, UK, EU and Japanese sizes.
Frequently asked questions
How do I measure for skirting board?
Measure the perimeter of the room, subtract door openings, and add a waste allowance for mitres. Then divide by the available length and round up.
How much waste should I allow?
Ten percent for a plain rectangular room and more where there are many corners. A mitre cut wrong is a wasted piece rather than a shortened one, which is what the allowance covers.
What is the difference between a mitre and a scribe?
A mitre cuts both pieces at 45 degrees to meet at a corner. A scribed joint cuts one piece to the profile of the other, which handles out-of-square corners far better and does not open up as timber shrinks.
Should skirting go on before or after flooring?
Usually after, so the skirting covers the expansion gap that floating floors need. Carpet is the exception — it is fitted after, tucked under the skirting edge.
How do I handle an out-of-square corner?
Measure the actual angle and halve it, rather than assuming 45 degrees. Few rooms are truly square, and a mitre cut to the assumption leaves a visible gap.
Should I buy longer lengths than the longest wall?
If they are available, yes. A join in the middle of a long visible wall is the most obvious flaw in a skirting installation, and a single length avoids it.
What height should skirting be?
Traditionally taller in rooms with high ceilings — 120 to 220 mm is the common range. Proportion to the room matters more than any standard, and period properties often used much taller.
How is skirting fixed?
Adhesive, nails, or screws into plugs depending on the wall. Adhesive alone works on a flat wall and struggles on an uneven one, where mechanical fixings pull it in.
Should skirting be fitted before painting the wall?
Painting the wall first and cutting in above the skirting is usual, though priming the skirting before fitting saves considerable time either way.
How do I fill the gap above skirting?
Flexible decorator's caulk, not rigid filler. The wall and the timber move relative to each other, and rigid filler cracks along the line within a year.
What is architrave and how is it different?
Architrave frames a door or window opening; skirting runs along the base of a wall. They are usually matched in profile, and the architrave is fitted first so skirting butts into it.
Can I fit skirting over carpet?
No — skirting goes on first and carpet is tucked under its edge. Fitting skirting on top of carpet makes future carpet replacement far more difficult.
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