Panel count decides everything else
Round down to a whole number of panels, then the stile count is simply panels + 1 (a vertical stile sits between every panel and at both ends). For a 12-foot (366 cm) wall with 18-inch (46 cm) target panels and 3-inch (8 cm) stiles: (366 + 8) ÷ (46 + 8) = 6 panels, so 7 stiles.
Your real panel width won't equal the target
Rounding down leaves slack that gets spread evenly across the panels. So the width you actually build is a bit wider than the width you asked for. Cut to the real width, not your target, or the last panel won't fit.
Six panels on the 366 cm wall leave 320 cm after 7 stiles, so each panel is 320 ÷ 6 ≈ 48.3 cm, not the 46 cm you entered. The leftover always widens the panels.
Linear material for each part
| Part | Amount needed |
|---|---|
| Stiles (verticals) | (panels + 1) × wall height |
| Rails (top, bottom, cap) | 3 × wall length |
| Surround trim | 2 × wall height + wall length |
| Panel material | real width × (height − top − bottom rail) × panels |
Panel height is the wall height minus the top and bottom rail heights, since the rails cover the top and bottom of the field. Add a middle rail's length (one more × wall length) if you run one.
Standard sizes and materials
- Height. 32–36 in for 8-ft ceilings, 42–48 in for 9–10-ft ceilings — roughly one-third of the wall.
- Panels and stiles. Panels run 12–18 in wide; stiles 1.5–4 in. Narrow stiles and wide panels read modern; wide stiles read traditional.
- Material. MDF is cheap and smooth but swells with moisture; PVC and vinyl are waterproof for bathrooms; natural wood (oak, maple) is the premium look.
Common questions
How high should wainscoting be?
The classic rule is one-third of the wall height, so about 32 to 36 inches for an 8-foot ceiling. For 9 to 10-foot ceilings raise it to 42 to 48 inches to keep the proportions balanced.
How many panels do I need for a wall?
Take the wall length plus one stile width, divide by the panel width plus one stile width, and round down. A 12-foot wall with 18-inch panels and 3-inch stiles gives 6 panels.
Can I put wainscoting in a bathroom?
Yes, but skip MDF because it swells with moisture. Use PVC or vinyl, which are waterproof, easy to wipe down, and resist mold.
