Skirting Board Calculator
How much skirting board (baseboard) a room needs — the perimeter less the doorways, with a cutting allowance — and how many standard lengths to buy.
Measure the room’s perimeter (twice length plus twice width for a rectangle), subtract each doorway, and add about 10% for mitres, scribes and the offcuts that are too short to use.
How the skirting board calculator works
Measure the room’s perimeter (twice length plus twice width for a rectangle), subtract each doorway, and add about 10% for mitres, scribes and the offcuts that are too short to use. Divide by the lengths your supplier sells — 2.4, 3.6 or 5.4 m; 8, 12 or 16 ft — rounding up. Longer boards mean fewer joins on long walls.
Formula: length = (perimeter − doorways) × 1.1; boards = ceil(length ÷ board length)
Worked examples
| Inputs | Boards to buy | Note |
|---|---|---|
| 5 × 4 m room, one door, 3.6 m boards | 6 | 17.1 m → 6 boards |
| 16 × 13 ft room, two doors, 12 ft boards | 5 | 57.2 ft → 5 boards |
| Hallway 8 × 1.2 m with three doors, 5.4 m boards | 4 | 17.3 m → 4 boards |
FAQFrequently asked questions
How much allowance should I add?
Ten percent covers mitred corners and the short offcuts you cannot use. A room with many alcoves or a bay window needs 15%; a plain rectangle with 5.4 m boards can get away with 5%.
Which board length is best?
The longest you can transport: a 5.4 m board runs a whole wall without a join. Plan each wall’s cuts before buying so that offcuts from long walls do the short returns.
What about built-in wardrobes and kitchen units?
Subtract their runs as openings — skirting goes behind neither. Add them back if the units sit on legs with a plinth you will not be fitting.
Do I need the same for architrave or cornice?
Cornice follows the same perimeter without subtracting doorways. Architrave is per opening: two legs and a head, about 5.2 m per standard door.
Where these figures come from
- The Engineering ToolBox — material densities, coverage and unit data — bulk densities, concrete at 2,400 kg/m³, board and sheet sizes
- Brick Development Association — brick sizes and quantities — 215 × 102.5 × 65 mm, 60 bricks per m²
- UK Government — Approved Documents (Building Regulations) — Building Regulations guidance
Last checked: September 2026. Coverage rates and material sizes are typical manufacturer figures — check the product you buy.