Baseboard Calculator
Last updated: 2026-05-07
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| Room perimeter (m) | Number of doors (pcs) | Board length (m) | Door width (m) | |
|---|---|---|---|---|
| Small door | 9 m | 1 pcs | 2.4 m | 0.9 m |
| Standard door | 13.5 m | 2 pcs | 2.4 m | 0.9 m |
| Large door | 18 m | 2 pcs | 2.4 m | 0.9 m |
| Window | 27 m | 3 pcs | 2.4 m | 0.9 m |
| Bay window | 36 m | 4 pcs | 2.4 m | 0.9 m |
What is the Baseboard Calculator?
Baseboards (skirting boards) run along every wall at floor level — calculating the right linear metres means measuring the full room perimeter, subtracting door openings, and adding waste for mitre cuts at corners. Get it wrong and you'll have visible joins or run short mid-room.
You may also find the Crown Molding Calculator, Decking Calculator, and Laminate Flooring Calculator useful.
Who Uses This Calculator?
This tool is used by homeowners finishing a renovation, carpenters quoting trim work, and builders specifying finish materials.
How to Use the Baseboard Calculator
- Enter your Room perimeter.
- Enter your Door width.
- Enter your Number of doors.
- Enter your Board length.
- Click Calculate to see your results instantly.
Formula
The calculator uses the following formula:
Net perimeter = room_perimeter - (doors × door_width); Boards = ceil(net_perimeter × 1.05 ÷ board_length)
Worked Example
A 5 m × 4 m room with two 0.9 m door openings needs (18 - 1.8) × 1.05 = 17 linear metres of baseboard allowing for waste.
Step-by-Step Calculation
- Gross perimeter: 18 m
- Subtract door openings: 2 × 0.9 m = 1.8 m → 16.2 m net
- Add 5% for cuts: 16.2 × 1.05 = 17.01 m
- Boards (2.4 m each): ceil(17.01 ÷ 2.4) = 8 boards
Common Mistakes to Avoid
- Including door openings in the perimeter instead of subtracting them
- Forgetting to account for inside corners where boards meet
- Not allowing for end cuts — the offcut from one wall can often start the next
Frequently Asked Questions
Measure the perimeter of each wall, subtract all door openings (measure between door jambs), then add 5–10% for mitre cuts at corners and waste. This calculator does all of that automatically.
70–90 mm is standard for rooms with 2.4 m ceilings. Use taller baseboards (100–140 mm) in rooms with higher ceilings to maintain visual proportion. Very tall ceilings (3 m+) can use 150 mm or taller profiles.
Hard flooring (tile, timber, laminate) should be installed first, then baseboard on top to cover the expansion gap. Carpet is typically laid after baseboard, with the carpet tucked under the board.
Most corners are not exactly 90 degrees. Use an angle finder or digital protractor to measure the actual angle, then divide by 2 for each mitre cut. Small gaps can be filled with caulk and painted.
Yes — thin MDF baseboard (6–9 mm) can be bent around gentle curves with a heat gun or by scoring the back. For tight curves, use purpose-made flexible trim or build up the curve with multiple layers of thin strips.