How to use this calculator
- 1Measure the width of each wall to be wainscoted, and count how many walls of that size there are.
- 2Set the wainscot height. Chair-rail height is classically about a third of the room height — usually 32–36 in (0.8–1 m).
- 3Take off openings that interrupt the wainscot, such as a doorway, with the openings box.
- 4Pick the board: beadboard planks, shiplap, tongue-and-groove or full sheets. A preset fills in the size; type your own for other boards.
- 5Each full-length plank is cut into wainscot-height pieces, so little is wasted — the calculator counts the pieces and the planks to buy with spare.
The formula
- 01Columns = wall width ÷ board width, rounded up per wall
- 02Pieces per board = board length ÷ wainscot height, rounded down (at least 1)
- 03Boards = columns ÷ pieces per board × (1 + spare %), rounded up
Wainscoting is the wall panel calculation at a low height: the boards stand side by side up to the chair rail, so the count across the wall is the wall width divided by the board width.
Because the boards are much longer than the wainscot is high, each one is cut into two or more full-height pieces — an 8 ft plank gives two 3 ft pieces plus an offcut — which is why wainscoting uses far fewer boards than full-height panelling.
The chair rail, skirting and any cap moulding are bought by length separately; the baseboard calculator works those out from the same wall measurements.
Worked example
A wall 12 ft wide with wainscoting 3 ft high takes 42 beadboard strips of 3.5 in side by side.
Each 8 ft plank cuts into full-height pieces, so with 10% spare you buy 24 planks.
Tips before you buy
- Set the height with a level line all round the room first — floors are rarely level, and the chair rail shows every wobble.
- Start each wall from its most visible corner or the centre, so the narrow cut strip lands in the least visible corner.
- Paint or prime the boards (especially the tongues and grooves) before fitting; shrinkage in winter otherwise shows unpainted lines.
- Keep the offcuts: the pieces left from each plank often cover the short wall sections beside doors and windows.
- Finish the top with a chair rail or cap moulding and the bottom with the skirting — the baseboard calculator counts those lengths.
Frequently asked questions
How much wainscoting do I need?
Measure each wall's width and set your wainscot height, and the calculator counts the strips across each wall, how many full-height pieces each plank yields, and the planks to buy with 10 % spare. The worked example above shows a typical wall.
How high should wainscoting be?
The classic rule is about one third of the room height: 32–36 in (0.8–1 m) in a standard room, which puts the cap at chair-rail height. Taller schemes at 48–60 in suit hallways and bathrooms — type any height.
What is the difference between wainscoting, beadboard and panelling?
Wainscoting is any panelling that covers the lower part of a wall. Beadboard — narrow planks with a grooved profile — is its most common form; flat panels, shaker frames and shiplap are others. For full-height walls use the wall panel calculator.
Do I need to remove the skirting board first?
Usually no: beadboard is often fitted on top of the wall and finished against the existing skirting, or the skirting is replaced after fitting. If the panel sits behind the skirting, add the skirting height to your wainscot height.
How do I work out the chair rail and cap lengths?
They run the same length as the walls you panel, minus openings. The baseboard & trim calculator counts those lengths, with waste and the pieces to buy.
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Sources
- Board counts: the same method as our wall panel calculator (full-height pieces cut from each board, 10 % spare) — see its page for the formula and tests.
- Wainscot heights: about one third of the room height, typically 32–36 in with the chair rail — the classic joinery proportion repeated in US and UK trim guides.
Formulas last reviewed: September 30, 2026 ·How we check our formulas