Skirting board calculator
Skirting length around a room, less doorways, cut into planks.
Fill in the fields and the result will appear here automatically.
Skirting follows the perimeter rather than the area, and both common mistakes sit on either side of that. The first is forgetting to deduct the doorways and buying too much. The second, and the costlier one, is deducting them and leaving no allowance: every corner eats length in the mitre cut, and on a room with five corners that shows. Planks are rounded up, because a shop will not sell half of one.
How it works
Formula and logic
Perimeter P = 2(L + W); deduction = n·b, where n is a nonnegative safe whole opening count and b is their common or mean width in m. Net length P − n·b must be positive. With reserve R = (P − n·b)(1 + w/100), pieces = ceil(R/stock length), purchased length = pieces·stock length. Reserve is finite and nonnegative. Individual wall cuts, corners and connectors are not optimized.
Example
A 5.2×3.4 room with two 0.9 m doorways needs 16.17 m of skirting — seven 2.5 m planks.
Fields and units
- Room length — m
- Room width — m
- Doorways — unitless
- Doorway width — m
- Plank length — m
- Cutting allowance — %
How to use
- — Enter rectangular room length and width in m.
- — Enter a whole count of spans without skirting and their common or mean width.
- — Enter stock-piece length and your chosen reserve percentage.
- — Check the separate cut and connector plan.
Method and limitations
- Calculation method
- Formula and logic
- Limitation
- Individual wall cuts, corners and connectors are not optimized.
FAQ
Why an allowance if the perimeter is known exactly?
The reserve is your chosen cutting allowance, while rounding whole pieces adds further length. Losses depend on walls, corners, joints and reuse of offcuts; neither 5 nor 10% is universal and cuts are not always 45°.
Should doorways be deducted?
Deduct only spans without skirting. If skirting continues under an arch, do not count that arch as a deduction; there is no need to add its width back after deducting zero. For unequal openings use their mean width and a whole count.
How do I handle an irregular room?
Measure the full perimeter P manually. To reproduce that length use L = W = P/4, or any positive L and W with L + W = P/2. Entering P/2 in both fields would double the perimeter. Actual corners and cutting layout are not modeled.
Should I count skirting behind furniture?
Usually yes: skirting is often fitted behind built-in units so the joint stays covered if things are moved. If you are certain it is not needed, deduct that length as an extra doorway.