How much board and batten?
Type the wall size, the batten width and the widest gap you want. The board and batten calculator finds the fewest battens with equal gaps from edge to edge, and counts the boards.
- Vertical battens
- 9
A 12 ft wall takes 9 vertical battens with 15.188 in gaps, 12 boards in all.
- Gap between battens
- 15.188 in
- Center to center
- 17.688 in
- Length of each vertical batten
- 93.5 in
- Total batten length
- 82.13 ft
- Boards to buy
- 12
Vertical battens: 9. A 12 ft wall takes 9 vertical battens with 15.188 in gaps, 12 boards in all.
How to calculate
A board and batten calculator for a wall: how many vertical battens fit with even gaps no wider than you choose, the exact gap, horizontal rails, the total length and the boards to buy.
Example with the default inputs (Wall width 12 ft, Wall height 8 ft, Batten width 2.5 in, Gap between battens, at most 16 in, Horizontal rows 1, Board length 8 ft, Extra for waste 10%): A 12 ft wall takes 9 vertical battens with 15.188 in gaps, 12 boards in all.
Method: Battens n = ⌈(W − b) ÷ (g + b)⌉ + 1 (at least 2); gap = (W − n × b) ÷ (n − 1); vertical length = H − rows × b; total = n × vertical + rows × W; boards = ⌈total × (1 + waste ÷ 100) ÷ board length⌉.
- Battens run from edge to edge: one at each end of the wall, with equal gaps between.
- Horizontal rows run the full wall width, and the vertical battens fit between them.
- Boards are counted by total length; the count does not plan each cut. Waste is 10% by default.
Worked examples
Each example is checked against the calculator on every build.
- Wall width 12 ft, Wall height 8 ft, Batten width 2.5 in, Gap between battens, at most 16 in, Horizontal rows 1, Board length 8 ft, Extra for waste 10% gives Vertical battens 9, Gap between battens 15.188 in, Total batten length 82.13 ft, Boards to buy 12.Source: OpenStax Prealgebra 2e, section 9.4 (length and area of rectangles, https://openstax.org/books/prealgebra-2e/pages/9-4-use-properties-of-rectangles-triangles-and-trapezoids); NIST Handbook 44 (1 in = 2.54 cm)
- Wall width 10 ft, Wall height 5 ft, Batten width 3.5 in, Gap between battens, at most 12 in, Horizontal rows 2, Board length 8 ft, Extra for waste 0% gives Vertical battens 9, Gap between battens 11.063 in, Total batten length 59.75 ft, Boards to buy 8.Source: NIST Handbook 44 (1 in = 2.54 cm)
How it works
With W the wall width, H the height to cover, b the batten width, g the largest gap you want and r the number of horizontal rows:
- Vertical battens n = ⌈(W − b) ÷ (g + b)⌉ + 1, and at least 2. This is the fewest battens, with one at each edge, whose equal gaps are no wider than g.
- Gap between battens = (W − n × b) ÷ (n − 1).
- Center to center = gap + b.
- Length of each vertical batten = H − r × b.
- Total batten length = n × (H − r × b) + r × W.
- Boards to buy = ⌈total × (1 + waste ÷ 100) ÷ board length⌉.
⌈x⌉ means x rounded up to a whole number. The gap and center spacing show to 3 decimals and the batten length to 2 decimals in inches (centimetres in Metric); the total shows to 2 decimals in feet (metres in Metric); all rounded half up.
Exact arithmetic. Each size is read as the exact decimal you typed, in the unit you typed it in (a feet-and-inches pair counts by its value in inches), and board lengths are exact (8 ft = 2.4384 m). Every step is exact, so a gap that comes out to exactly the most you asked for is kept.
Board lengths: 6, 8, 10, 12 and 16 ft; 2.4, 3.0 and 3.6 m.
Rules
- The wall width is from 1 cm to 100 m; the height from 1 cm to 30 m; the batten width from 1 mm to 1 m; the gap from 1 mm to 10 m.
- Horizontal rows: a whole number from 0 to 20. Waste: 0% to 100%.
- A wall narrower than two battens has no answer: "The wall is narrower than two battens side by side."
- Rows that take the whole height have no answer: "The horizontal rows take up the whole height of the wall."
Worked examples by hand
A 12 × 8 ft wall, 1×3 battens, gaps of at most 16 in, a top rail, 8 ft boards, 10% waste. W = 144 in, H = 96 in, b = 2.5 in. (144 − 2.5) ÷ (16 + 2.5) = 7.65, so n = 8 + 1 = 9. Gap = (144 − 9 × 2.5) ÷ 8 = 15.1875 in; center to center 17.6875 in. Each vertical is 96 − 2.5 = 93.5 in. Total = 9 × 93.5 + 144 = 985.5 in = 82.125 ft. Boards = 985.5 × 1.1 ÷ 96 = 11.29, so 12.
A 10 ft wide, 5 ft high wainscot, 1×4 battens, gaps of at most 12 in, two rails, no waste. W = 120 in, H = 60 in, b = 3.5 in. (120 − 3.5) ÷ 15.5 = 7.52, so n = 9. Gap = (120 − 31.5) ÷ 8 = 11.0625 in. Verticals 60 − 7 = 53 in. Total = 9 × 53 + 2 × 120 = 717 in = 59.75 ft. Boards = 717 ÷ 96 = 7.47, so 8.
Other questions people ask
How do I space board and batten evenly?
Put a batten at each edge of the wall and space the rest equally. With n battens of width b on a wall W wide, each gap is (W − n × b) ÷ (n − 1). The calculator picks the fewest battens that keep the gap no wider than you ask.
How many battens do I need for a 12 ft wall?
With 1×3 battens (2.5 in face) and gaps of at most 16 in: (144 − 2.5) ÷ (16 + 2.5) = 7.65, round up to 8, add 1: 9 battens, each gap exactly 15.1875 in (15 3/16 in).
What is a good batten spacing?
It is a matter of taste and of the wall. Accent walls often use gaps of 12 to 24 in; narrower gaps look busier, wider ones more open. Try a few values and pick the gap you like.
What size boards are battens?
Common choices are 1×2 (1.5 in face), 1×3 (2.5 in) and 1×4 (3.5 in) boards, or strips of MDF or plywood. Use the actual face width, not the nominal size.
Does it count a top rail?
Yes: set Horizontal rows to 1 for a top rail, 2 for a top and middle rail, or 0 for vertical battens only. Each row runs the full wall width, and the vertical battens are shortened to fit between the rows.
How many boards should I buy?
The calculator adds up the length of every batten, adds 10% for waste by default, and divides by the board length. Short pieces can often come from the same board, but buy a spare or two for knots and mistakes.