YepCalc

Wainscoting Calculator

Lay out frame-and-panel wainscoting on each wall. Enter the wall lengths, the stile width, and a target panel width or a number of panels, and the calculator finds the panel width, the stile spacing, and where to mark each stile. Add the frame height to see how many boards to buy for the stiles and rails.

Choose how to size the panels

Walls

Wall 1

Enter Length to include this wall.

Add each wall or run of wainscot, measured end to end.

Panels and stiles

Use the actual width, such as 3 1/2 in for a 1x4.

The panel width you'd like, such as 15 to 20 in. Each wall's panels are sized to fit exactly.

Height and boards

From the bottom of the bottom rail to the top of the top rail, without the baseboard or cap. With no bottom rail, measure from the top of the baseboard. Wainscot is often 30 to 42 in tall, or about a third of the wall height.

Default: 2 (a top and a bottom rail)

Rails run the full length of every wall. Use 1 if the baseboard serves as the bottom rail.

Default: 8 ft

The length the boards are sold in, such as 8, 12, or 16 ft.

Waste and cost

%

Recommended for trim boards: 10%

per

Result

Enter the length of a wall to see the layout.

How to calculate a wainscoting layout

Each wall gets a stile at both ends and stiles in between, with equal panels between them. With n panels, there are n + 1 stiles. When you size by a target width, the number of panels on each wall is:

Panels = (wall length − stile width) ÷ (target panel width + stile width), rounded to the nearest whole number

An exact half rounds up, so the panels come out a little narrower than the target. Every wall gets at least one panel, and never so many that the panel width would be zero. Then each wall is split evenly:

Panel width = (wall length − stile width × (panels + 1)) ÷ panels

On center = (wall length − stile width) ÷ panels

Stile mark = stile number × on center, counting the first stile as 0

For a 12 ft (144 in) wall with 3 1/2 in stiles and an 18 in target, (144 − 3.5) ÷ 21.5 = 6.53, so 7 panels. The panels are (144 − 28) ÷ 7 = 16 9/16 in wide and the stiles 140.5 ÷ 7 = 20 1/16 in on center.

Each Stile mark is the distance from the left end of the wall to the left edge of a stile, so you can line the edge of each stile up with its mark. Each mark is worked out on its own and then rounded, so the rounding doesn't add up along the wall, and the last mark is exactly the wall length minus one stile width. For the center of a stile, add half the stile width to its mark.

Stiles, rails, and boards to buy

Stile length = frame height − rails × stile width

Rail length = rails × total wall length

Boards to buy = (stiles ÷ stiles cut from each stock length + rail length ÷ stock length) × (1 + waste % ÷ 100), rounded up

The rails are the same width as the stiles and run the full length of every wall, and the stiles fit between them. Stiles are full pieces, so the calculator counts how many fit in one stock length. Rails can be joined, and offcuts are reused, so their length is divided by the stock length. Because stiles and rails come from the same boards, the two are added before rounding up.

How to measure for wainscoting

Walls, doors, and windows

Measure each wall where the wainscot goes, from end to end. Doors and windows split a wall into runs: Fine Homebuilding's Lynn Hopkins puts an end stile next to the side casing of each door and window. Add each run as its own wall. For the run under a window, enter the length under the window. Its panels will be their own width, which is normal.

Corners

The calculator puts a stile at both ends of every wall, so two stiles meet at each inside corner. Hopkins suggests either two stiles at every inside corner or none at all, and a stile on both sides of each outside corner.

If one wall's corner stile laps over the other wall's wainscot, install the first wall and measure the second wall to the face of the first wall's wainscot. In other words, enter the second wall shorter by the board thickness, such as 3/4 in. Fine Homebuilding's Gary Striegler makes the lapped stile wider by that thickness.

Stile width and frame height

Enter the actual width of your boards, not the nominal one. In the US softwood lumber standard PS 20-20, a dry 1x4 is at least 3 1/2 in wide, and This Old House builds the stiles and rails from primed 1x4 pine. With a nominal 4 in, every panel comes out narrower than it should. The Metric 94 mm is a planed 25 × 100 mm board at UK merchant Wickes. Others sell the same size at 95 mm, so measure the boards you have.

The frame height runs from the bottom of the bottom rail to the top of the top rail, without the baseboard or the cap. If the baseboard serves as the bottom rail, measure from the top of the baseboard and set Rails to 1. If the bottom rail is a different width from the stiles, leave it out of the frame height, set Rails to 1, and count the bottom rail separately.

Picture frame molding layout

Wall frames made of picture frame molding use the same layout. Enter the space between frames as the Stile width and set Rails to 0. The panel width is then the outside width of each frame, and each frame's left edge is its Stile mark plus the space. This Old House's example of three frames on a 60 in wall, 3 in apart, gives frames (60 − 3 × 4) ÷ 3 = 16 in wide, with the left edges at 3, 22, and 41 in.

This Old House keeps the space between frames between 2 3/4 and 3 1/2 in, the same all around the room. The boards to buy count stile and rail boards, not molding. For the molding, each frame takes 2 × (width + height).

Wainscoting height and panel width

Height and panel width are a matter of looks, so neither has a default. These guides from the sources are a starting point:

Guide Typical size
Wainscot height (Lynn Hopkins) 30 to 42 in, or a third to two-fifths of the way up the wall
Wainscot height (This Old House) 36 to 42 in for classic wainscot, taller for modern
Panel width (Andrew Young) 15 to 20 in (about 400 to 500 mm)
Panel shape (Lynn Hopkins) Often a 3:5 rectangle
Panel shape (Gary Striegler) Wider than tall, in an odd number

With 1 or 2 rails and a frame height, the calculator shows how tall the panels are between the rails, so you can compare the panel width and height and adjust. Hopkins finds panels look best when the same width repeats around the room, which is why Target panel width is the default. She also shows layouts where only the end panel of a wall differs; this calculator splits each wall evenly instead.

The stock length starts at 8 ft (2.4 m), the shortest length of 1x4 poplar boards from Alexandria Moulding and the length of Wickes's 94 mm boards. Enter the length you can buy. The 10% waste allowance follows Alexandria Moulding's advice to add 10% to trim.

Examples

A 12 ft wall

A 12 ft wall with 3 1/2 in stiles and an 18 in target gets 7 panels 16 9/16 in wide and 8 stiles 20 1/16 in on center. With a 32 in frame and 2 rails, each stile is 25 in long and the panels are 25 in tall. The stiles and rails come to 40.67 ft, or 44.73 ft with 10% waste. Three stiles come from each 8 ft board, so that's 7 boards of 8 ft, $52.50 at $7.50 each.

A room

Walls of 12, 10, 12, and 10 ft with the same 18 in target get 7, 5, 7, and 5 panels. The 10 ft walls have panels 19 13/16 in wide. That's 24 panels and 28 stiles, and with a 32 in frame, 23 boards of 8 ft, $172.50 at $7.50 each.

A Metric wall

A 3.6 m wall with 94 mm stiles and a 450 mm target gets 6 panels 490.3 mm wide, 584.3 mm on center. With an 800 mm frame, each stile is 612 mm, and the stiles and rails come to 12.63 m with 10% waste, or 6 boards of 2.4 m. At £4.50 per m, that's £56.85.

FAQ