Wainscoting calculator.
Panel sizes, mitre cuts and the sticks to buy — in sixteenths.
For p panels on a wall of width L with stiles of width w, there are p + 1 stiles and each panel is (L − (p + 1) × w) ÷ p wide. Panel height is the cap height minus the chair rail, the baseboard and the rails. A 144-inch wall, four panels, 3½-inch stiles: 31 5/8 inches.
02 / Your wall
TO SCALE| Member | Left edge | Centre | Right edge |
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03 / What to cut
- Panel height
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- Proportion
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- Cap sits at
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- Wainscoted area
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- Moulding in total
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- Sticks to buy
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Panel height comes off the elevation, not the wall: cap, less the chair rail, less the baseboard, less what the rails or reveals take.
Every piece, and the sticks they come off.
| Piece | Qty | Length | Total |
|---|
The two lengths every mitre has
A frame side cut at 45 degrees is longer on its outside edge than on its inside. Set the stop to the long point and the short point falls where it should; measure the short point by mistake and the frame comes up two moulding widths small. Nothing in this search result prints both, so here they are.
| Side | Qty | Long point | Short point |
|---|
The cutting plan
| Stick | Cuts | Offcut |
|---|
Which stick length costs least
Trim is sold by the stick, so the length you pick changes the bill without changing the wall. The column that matters is the offcut: it is the material you pay for and throw away.
| Stock length | Sticks | Offcut | Offcut total |
|---|
Lengths seen in stock on 2026-09-09: 8, 10, 12 feet. 16-foot is offered because it is common in pine, and marked unverified because it was not observed on the MDF references in that check.
Two formulas, and one judgement
Wainscoting is laid out twice: once across the wall, once up it. Across, the wall is shared between vertical members and the panels between them. Up, the cap height is spent on the chair rail, the baseboard and whatever frames the panel above and below.
Worked example: a 12-foot wall, four panels
Take a wall 144 inches between corners in the stile-and-rail style, four panels, stiles of primed MDF 1×4 — actual width 3½ inches, not 4. Four panels need five stiles, because the wall starts and ends with one.
- Stiles take 5 × 3½ = 17½ inches of the wall.
- 144 − 17½ = 126½ inches of panel, over four panels: 31 5/8 inches each.
- With the cap at 32 inches and a 2½-inch chair rail, the field is 29½ inches.
- Take a 3½-inch top rail and a 5½-inch bottom rail: the panel is 20½ inches tall.
That panel is wider than it is tall, at 0.65 to 1. It is the moment to add a panel rather than accept it: five panels on the same wall give 24 5/8 inches and a proportion of 0.83, six give 19 15/16 inches and 1.03 — square, which is the other end of the same mistake. The calculator reports the ratio for this reason, and never changes your layout for you.
How high, and where the number comes from
The traditional guide is one third of the wall height, cap and mouldings included. Our source puts it plainly: “The traditional rule of thumb is that wainscoting height should be a third of the wall's height, including the cap or any moldings.” We class it as a convention, not a rule, because no building code and no product standard sets it — and a carpenter in the trade thread we checked alongside it writes that you are “never limited to such numbers”. Two thirds is the current alternative, and half the wall is the one proportion trim guides tell you to avoid.
| Ceiling | Cap height | Two thirds | Basis |
|---|---|---|---|
| 8 ft | 32″ | 64″ | Stated by the source |
| 9 ft | 36″ | 72″ | Stated by the source |
| 10 ft | 40″ | 80″ | The one-third rule applied — a calculation, not a published figure |
One case suspends the rule, and the same source says so: “If the bottom of the window falls where you've measured one-third up the wall, you might make your wainscoting level with the bottom of the window.” A cap that dies into a window sill at an awkward height is the mistake the arithmetic cannot see, which is why openings are an input here and not an afterthought.
Applied frames or stile and rail
Applied picture frame moulding — box moulding, shadow box — is trim glued and nailed to a finished drywall wall, with reveals of bare wall between the frames. It is what most weekend installs actually are, and its cut list is four mitred sides per frame. Stile-and-rail is joinery: continuous stiles and rails with a recessed or raised panel between them, and its cut list is stiles, a top rail and a bottom rail in full lengths. The layout maths is identical; what you cut is not, and neither is what you buy.
Long point, short point
Every mitre has two lengths. The long point is the outside edge of the cut, the short point the inside, and they differ by twice the moulding width — 2½ inches on a 1¼-inch moulding. A frame 31 5/8 inches wide in that moulding has long points of 31 5/8 and short points of 29 1/8. Cutting to the wrong one is the most common way a frame ends up short, and the table above prints both so the mitre saw stop can be set once.
Flat panel, raised panel, beadboard
What fills the space between the stiles changes the look and the shopping list, not the layout. A flat or recessed panel is a sheet — often ¼-inch plywood or MDF — sitting behind the frame. A raised panel is a solid panel with a profiled edge, milled or bought, and it is the expensive version. Beadboard replaces panels altogether with a continuous grooved sheet or with tongue-and-groove boards, which is why beadboard walls have stiles only at the corners. This page lays out the frame; it does not price the fill, because we have not measured what those sheets cost.
What you cut it from
Primed MDF is the default here because it is what most of these walls are made of: stable, cheap, dead flat, and sold ready to paint. It hates water, so a bathroom below the splash line is a case for PVC trim, which cuts the same way and never swells. Poplar is the paint-grade hardwood for anything that will take knocks, and primed pine is the cheapest real wood. Widths match across all four at a given nominal size — a 1×4 is 3½ inches in any of them — so the layout does not change when the material does. Only pine and MDF carry our own measured figures; for poplar and PVC, read the Actual line on the product page.
Mitre it or cope it
Frames are mitred: four 45-degree cuts, long point out. Where a chair rail meets another chair rail in an inside corner, a coped joint holds a paint line better than a mitre, which opens as the house moves. Outside corners are mitred, and the piece has to be cut long enough to reach the far side of the return — a detail the cut list cannot know, because it does not know where your corners are.
What lands on a window, an outlet or a switch
Enter an opening with its distance from the left corner and its width. Any stile or reveal that overlaps it is drawn hatched, flagged in the position table and dropped from the cut list. It is not quietly moved: shifting one member breaks the even rhythm the layout exists to create. Electrical outlets are the same problem at a smaller scale — a receptacle that falls on a stile is a decision about the layout, and the drawing is what lets you take it.
Before you cut
How do I calculate how much wainscoting I need?
Work out the layout first, then read the cut list. Panels come from (wall width − stiles × stile width) ÷ panels; the material you buy comes from adding up every piece length and packing those lengths onto 8, 10 or 12 foot sticks. Square footage is the wrong unit for buying trim, and it is what most calculators give you.
How far apart should my wainscoting be?
There is no set spacing. Panels usually read best slightly taller than they are wide, so on a long wall you add panels rather than stretching them. Set the number of panels, look at the proportion the calculator reports, and adjust until it sits between about 1.1 and 1.6 to 1.
How high should wainscoting be with 8-foot ceilings?
About 32 inches. The traditional rule of thumb puts the cap at a third of the wall height, moulding included, and our source states it plainly for this case: “So if you have 9-foot walls, then 3-foot (or 36-inch) wainscoting will look great. Scale down to about 32 inches for rooms with 8-foot walls.” It is a convention, not a code requirement.
How to size wainscoting panels?
Width comes out of the wall: fix the stile or reveal width, choose how many panels, and the rest divides. Height comes out of the elevation: cap height, minus the chair rail, minus the baseboard, minus the rails or reveals above and below. Then judge the proportion — that part is a decision, not arithmetic.
Is this wainscoting calculator free?
Yes, and complete: layout, elevation drawing, mitre cuts, cut list, stick comparison, CSV and printable plan. No account, no email, nothing withheld.
Is there a wainscoting calculator app?
No app to install. The page works in a phone browser at the wall, the maths runs on your device, and the plan prints or exports so you can carry paper instead of a phone into a dusty room.
Does it do picture frame wainscoting?
That is the default style. Applied picture frame moulding, also called box or shadow box moulding, is laid out as reveals and frames, and the calculator returns the 45-degree long point and short point for every side. No other tool on this search does.
What about board and batten wainscoting?
Board and batten is a different layout: vertical battens spaced across the wall, with no frames and no panel proportion to judge. It has its own page here, with a spacer block width and a stock board comparison built for that job.
Can it lay out wainscoting on stairs?
Not yet, and we would rather say so than fake it. Raked panels on a staircase need the stair angle, and every panel is a different parallelogram. It is on the list; today this page handles flat walls only.
Does it work as a wall moulding calculator generally?
For anything laid out as frames or panels between a cap and a baseboard, yes — picture frame moulding on a full-height wall included: set the cap height to the wall height and leave the chair rail at zero.
What is a good wainscoting layout on a wall with a door or a window?
Enter the opening. Any stile or reveal that lands on it is flagged and the piece is dropped from the count, because a frame that runs into a door casing is not a frame. Our source makes one exception to the height rule for exactly this reason: if the window sill lands near your one-third mark, line the cap up with the sill.
How much extra material should I buy?
The waste box defaults to 10 %, which is what Google's own summary of this topic tells searchers to add, and you can change it. It is deliberately separate from the offcut column: offcuts are what your cutting plan actually wastes, spare sticks are insurance against a bad cut.
What this does not do
- One flat wall at a time. A whole room is four runs and four corners, and corner overlap is not modelled.
- No stairs. Raked panelling needs the stair angle and gives a different parallelogram for every panel; saying so is more useful than a wrong number.
- No cost. We have not sourced US trim prices we would publish with a date and a sample size, so no dollar figure appears here.
- No paint or primer quantities, for the same reason: coverage rates vary by product and we have not measured any.
- No fixing schedule. Brad length, construction adhesive, caulk and wood filler are trade decisions, not measurements.
- Each piece is cut whole from one stick; nothing is scarfed, and offcuts are not re-cut across sticks.
- Fractions display to the nearest 1/16 inch; the geometry underneath keeps full precision.