Enter each room by length × width or straight perimeter, subtract the doorways, and get the linear feet of baseboard and the number of stock lengths to buy - plus an optional second profile like crown or picture rail. In feet or metres.
Doorways & openings (no baseboard across these)
Baseboard run: 16.2 m
Common: 2.4, 3.0, 4.2 and 5.4 m.
Baseboard run
16.2 m
Wall perimeter
18.0 m
Openings deducted
1.8 m
Trim comes in fixed sticks - the cut allowance covers end-of-wall offcuts, but order a spare length for mitres on long walls.
Baseboard (skirting) is a linear job: it runs around the foot of the walls, so you size it from the room perimeter, not its floor area. The only thing that shortens the run is a doorway or other opening, where the trim stops at each side:
perimeter = 2 × (length + width) (or enter the perimeter directly)
run = perimeter − doorway widths (per room, never below zero)
total run = sum of every room's run
lengths = ceil( total run × wastage ÷ stock length )
Each room’s doorways are subtracted from that room only and clamped at zero, so a wide opening in one room can never pull another room’s run negative. The runs are then pooled and rounded once to whole stock lengths, because an offcut from one wall can start the next. An optional second profile - crown molding, coving or picture rail - is sized off the full perimeter with no doorway deductions, since a run at the ceiling line is not interrupted by doors.
This example follows the unit system you pick in the calculator above.
A 5 × 4 m living room with two 0.9 m doorways, baseboard in 4.2 m lengths, 10% waste:
Subtract the width of each doorway or cased opening - not windows, which the baseboard runs beneath. Typical widths to deduct:
| Opening | Width (ft) | Width (m) |
|---|---|---|
| Single interior door (with frame) | ~2.8 ft | ~0.85 m |
| Wide / accessible door | ~3.3 ft | ~1.0 m |
| Double door / French doors | ~5.5 ft | ~1.7 m |
| Cased opening (no door) | 4 - 6 ft | 1.2 - 1.8 m |
| Sliding / patio door | 6 - 8 ft | 1.8 - 2.4 m |
Measure your own openings where you can - frames vary - but these are good defaults when you are estimating from a floor plan.
In Canada, the floor trim is called baseboard and the trim around doors and windows is the casing. It is usually finger-jointed pine, solid wood or primed MDF, sold in 8, 12, 14 and 16 ft lengths, in profiles such as colonial, ranch (WM 713) and ogee (WM 623). Buy the longest length that fits each wall so you join less and waste less, and set your stock length above to match what is on the shelf.
For the common profiles and sizes near you, see the WM-series profiles of the Moulding & Millwork Producers Association.
Measure the perimeter of each room - for a rectangle that is 2 × (length + width) - then subtract the width of every doorway and cased opening, because baseboard does not run across them. Add the rooms together for the total run, add 10% for cuts and mitres, and divide by the length of one board to get how many to buy. The calculator does all of this; just enter each room and its doorways.
No - this sizes baseboard trim, the moulding along the bottom of the wall, in metres and how many lengths to buy. It does not size baseboard heating. If you are looking at hydronic or electric baseboard heaters, you need a heating estimate based on the room volume, insulation and climate, which is a different calculation. Use this tool for the wood or MDF trim itself.
Floor area only gives a rough guide, because baseboard follows the wall perimeter, not the floor. For a single open square room the perimeter is about 4 × the square root of the area, so 110 m² is near 42 m. A real home that size is split into rooms by internal walls, which adds perimeter, and has doorways, which take some away, so it usually lands around 55 to 75 m. Enter each room above for the real figure rather than estimating from the floor area.
Subtract doorways and floor-to-ceiling openings, since the baseboard stops at each side of them. Do not subtract windows - the baseboard runs along the wall underneath a window unless it sits right on the floor. Enter each doorway width in the room and the calculator removes it from that room only, so a wide opening in one room never eats into another room's run.
Take your total run, add a cut allowance (10% for simple rooms, 15% where there are lots of corners and short walls), then divide by the length of one board and round up. Buying the longest stock that fits each wall means fewer joints and less waste. The calculator turns your run straight into a length count at the size you pick.
Either works. For a plain rectangular room, enter the length and width and the calculator works out the perimeter. For an L-shaped or bay room, switch that room to "Perimeter" and walk the tape around the base of every wall, including the returns, then enter the single total. Mixing modes room by room is fine.
Baseboard (skirting board) runs horizontally along the bottom of the walls. Casing (architrave) is the trim that frames a door or window opening. They are different runs bought separately - this calculator sizes the baseboard. The "second profile" option is for another continuous run at the ceiling, like crown moulding or picture rail, not for casing.
Crown moulding, coving and picture rail run along the top of the wall where doors do not interrupt them, so they cover the full room perimeter with nothing deducted. Baseboard at the floor stops at each doorway. That is why the calculator sizes the second profile off the gross perimeter, not the shorter baseboard run.
Allow about 10% on a simple room and 15% where there are many corners, short walls or mitres - each mitre and scarf joint eats a little off the board, and the last offcut on a wall is often too short to reuse. It is cheaper to have one spare length than to stop and re-order a single board mid-job, especially if the profile is hard to match.
Material and labor cost per linear foot, plus removal and painting add-ons.
Read guide→Turn room size or square footage into linear feet of baseboard and lengths to buy.
Read guide→Turn room size into linear feet of crown molding and lengths to buy, corners included.
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