Baseboard Calculator
Enter the room's perimeter and the openings to skip, and this gives the linear feet of baseboard — and the number of stock pieces — to buy.
Baseboard needed
37.4linear ft
- Stock pieces
- 5 pieces
- Wall to cover
- 34 linear ft
How it’s calculated
Wall to cover = perimeter − openings (doorways get no baseboard). Linear feet to buy = that × (1 + waste), since miter cuts and offcuts waste a little at each corner. Pieces = linear feet ÷ stock length, rounded up. A chair rail uses the same math (it also breaks at doors and runs under windows). Crown molding is the exception — it runs at the ceiling, so it breaks at neither doors nor windows: set openings to 0 for crown.
Worked example
A room with a 40-ft perimeter and 6 ft of door openings: 40 − 6 = 34 ft to cover; × 1.10 = 37.4 linear ft; ⌈37.4 ÷ 8⌉ = 5 eight-foot pieces.
FAQs
- How do I find the perimeter?
- Measure along the base of every wall and add them up. For a simple rectangular room it's 2 × (length + width); for an L-shaped or bumped-out room, total each wall segment individually.
- Should I subtract doorways?
- Yes — cased openings and doorways get no baseboard, so subtract their total width. Don't subtract windows; baseboard runs underneath them. The calculator's “openings” field is for doorways and similar gaps. (Crown molding is different — it runs at the ceiling and breaks at neither doors nor windows, so set openings to 0 for crown.)
- Why round up to whole pieces?
- Trim is sold in fixed lengths, so you buy whole boards and cut to fit. Buying by the piece also lets you plan where the joints fall — longer stock means fewer seams on long walls. Keep an offcut for future repairs.
Sources
- Linear feet = (perimeter − openings) × (1 + waste); pieces = linear feet ÷ stock length, rounded up. Geometry.