Board and batten looks simple — vertical strips on a wall — but it only looks right when every gap is identical and the first and last battens sit tight against the corners. This calculator starts from the gap you'd like, finds the nearest layout that divides the wall evenly, and tells you the exact spacing to mark, the total length of trim and how many boards to buy.
How to use the board and batten calculator
- Measure the wall width corner to corner.
- Enter the batten height — the full wall height, or the height of a half-wall or wainscot design.
- Choose a target gap. 16 in is a balanced look; narrower gaps feel busier, wider gaps more modern.
- Enter the batten width — the actual width, not the nominal size.
- Choose whether to add a horizontal top rail, then the board length you plan to buy.
Board and batten spacing formula
Battens = gaps + 1
Exact gap = (W − battens × b) ÷ gaps
Trim length = battens × height + top rail
- W — wall width
- b — batten width
Rounding the number of gaps up means the exact gap is never larger than your target — it gets a little smaller so the spacing comes out even.
Worked example: a 12 ft bedroom wall
- Wall: 144 in wide, 1×4 battens (3.5 in), 16 in target gap
- Gaps: (144 − 3.5) ÷ (16 + 3.5) = 7.2 → 8 gaps, so 9 battens
- Exact gap: (144 − 9 × 3.5) ÷ 8 = 14.06 in (about 14 1/16 in)
- Trim: 9 battens × 8 ft + 12 ft top rail = 84 ft
- Boards: nine 8 ft battens plus two boards for the 12 ft rail = 11 boards
Marking the layout
Mark the edge of each batten, not its center. Starting from the left corner, the left edge of batten n is at (n − 1) × (gap + batten width). For the example above, battens start at 0, 17.56, 35.13, 52.69 in and so on — every 17.56 in. Use a story stick (a straight board with the marks on it) to transfer the layout quickly and consistently.
Batten count for common walls
1×4 battens (3.5 in), 16 in target gap.
| Wall width | Battens | Exact gap |
|---|---|---|
| 8 ft (96 in) | 6 | 15.00 in |
| 10 ft (120 in) | 7 | 15.92 in |
| 12 ft (144 in) | 9 | 14.06 in |
| 14 ft (168 in) | 10 | 14.78 in |
| 16 ft (192 in) | 11 | 15.35 in |
Tips
- Check the corners for plumb. Out-of-plumb corners make the end gaps look uneven; scribe the end battens to fit.
- Caulk and fill before painting. Caulk the batten edges and fill nail holes for a built-in look.
- Paint with a semi-gloss or satin — it highlights the shadow lines and wipes clean.
Painting the wall afterwards? The Paint Calculator estimates gallons.
Frequently asked questions
How far apart should board and batten be?
For interior accent walls, gaps of 12 to 24 inches are common, with 16 in a popular middle ground. The calculator adjusts your target so every gap is equal and the battens land at both ends of the wall.
How do I calculate board and batten spacing?
Subtract the total width of all battens from the wall width, then divide by the number of gaps. On a 144 in wall with nine 3.5 in battens: (144 − 31.5) ÷ 8 = 14.06 in between battens.
What size boards are used for board and batten?
1×3 (2.5 in actual) and 1×4 (3.5 in actual) are the most common for interior walls. MDF strips are popular because they are straight and paint smoothly.
Do I need a backer board?
On a smooth drywall wall, many people apply battens directly and paint everything one color. On textured walls, a thin panel (such as 1/4 in hardboard or MDF) behind the battens gives a smooth look.
Should battens go over outlets?
Plan the spacing so battens don't land on outlets and switches. If one does, shift the layout or notch around the box using a box extender as required for electrical safety.