Board and Batten Calculator
Find how many battens to buy for a board and batten wall, and how far apart to put them. The calculator spaces the battens evenly on each wall, at or under the space you choose. It also works as a board and batten siding calculator, counting wide boards and the battens that cover the gaps.
- Choose US or Metric. You can still change the unit of any single field.
- Choose a style. Battens only is for battens nailed over drywall, such as an accent wall, or over vertical siding panels. Boards and battens is for wide boards set side by side with a batten over each gap.
- Enter the length of each straight wall, measured end to end, and use Add wall for the next one.
- Enter the Wall height: the length of each vertical batten or board. For walls of different heights, work out each height separately.
- Enter the actual Batten width and, for battens only, the most Space between battens you want. For boards and battens, enter the board width and the space between boards instead.
- Optionally, enter Horizontal rows for a top rail or a grid, and check the stock lengths and the waste allowance.
- Optionally, enter a board price and a batten price, per piece or by length, to estimate the cost.
Length fields accept whole numbers, decimals, fractions, and mixed
numbers, such as 12, 10.5, 1/2, or
2 1/2. Choose ft + in as the unit to enter a
wall length such as 13 ft 6 in in two fields.
To set the battens by count instead, change the space and watch the Layout table: a smaller space adds battens, and a larger one takes them away.
How to calculate board and batten
Battens only
Each wall gets a batten at both ends and battens in between, with the space between them split evenly and no wider than the space you enter:
Battens per wall = (wall length + space) ÷ (batten width + space), rounded up
Actual space = (wall length − battens × batten width) ÷ (battens − 1)
On center = (wall length − batten width) ÷ (battens − 1)
Rounding up keeps every space at or under the one you enter, so the wall never looks sparser than you planned. A 12 ft wall with 2 1/2 in battens and up to 12 in between gets (144 + 12) ÷ 14.5 = 10.76, so 11 battens, 11 5/8 in apart and 14 1/8 in on center. If a short wall can't fit that many battens, it gets as many as fit, and its space comes out wider.
The calculator counts each wall on its own, because every wall needs its own end battens. Four walls of 12, 10, 12, and 10 ft at up to 16 in need 9 + 8 + 9 + 8 = 34 battens, while 44 ft divided at once gives only 30.
Boards and battens
Boards per wall = (wall length + gap) ÷ (board width + gap), rounded up
Battens per wall = boards − 1
Each gap between two boards gets one batten, so the battens are one board width plus one gap apart, center to center. The ends of the wall are left for corner trim. The last board on each wall is ripped to fit and counts as a whole board.
Length and pieces to buy
Batten length = (vertical battens × wall height + horizontal rows × total wall length) × (1 + waste % ÷ 100)
Battens to buy = (vertical battens ÷ battens cut from each stock length + horizontal batten length ÷ stock length) × (1 + waste % ÷ 100), rounded up
Boards to buy = boards × (1 + waste % ÷ 100) ÷ boards cut from each stock length, rounded up
Vertical battens and boards are full pieces the height of the wall. When the wall height is half the stock length or less, two or more are cut from each stock length. Horizontal battens run the full length of every wall, and joints and offcuts are reused, so their length is divided by the stock length. Because they're the same stock as the vertical battens, the two are added before rounding up, and the offcuts from the vertical battens can go into the horizontal rows.
Spacing, sizes, and stock lengths
How far apart to space battens
There's no single right spacing, which is why the space starts blank. Fiber cement maker Allura notes that closer battens look more dimensional and wider ones more subtle, and that on old board and batten walls the batten spacing was the board width. The Western Red Cedar Lumber Association suggests 1×3 battens with 1×10 boards, which puts the battens 9 3/4 in on center with a 1/2 in gap. Home site Bob Vila suggests drawing the wall to scale first, so you don't end up with a 12 in space at one corner and a 3 in space at the other. Splitting the wall evenly, as ProTradeCraft also recommends, avoids that.
If you think in on-center spacing, such as battens over the studs at 16 or 24 in on center on exterior panels, enter the on-center spacing minus the batten width: 13 1/2 in for 16 in on center with 2 1/2 in battens. Even spacing doesn't put every batten over a stud, so check where the studs are before you nail.
Wall height
Enter the length of each vertical batten, not always the full wall. Bob Vila puts the baseboard and the top trim up first and then cuts each batten to fit between them, with a half-height wall about 32 in up from the floor. On drywall, where nails don't hold well, the battens are glued with construction adhesive and nailed.
Batten and board sizes
Enter actual sizes, not nominal ones. In the US softwood lumber standard PS 20-20, a dry 1x2, 1x3, and 1x4 are at least 1 1/2, 2 1/2, and 3 1/2 in wide, and a 1x8, 1x10, and 1x12 are 7 1/4, 9 1/4, and 11 1/4 in. A nominal width gives too few battens and boards, so check the size on the product. HardieTrim battens from James Hardie, used with HardiePanel vertical siding, are 2 1/2 in wide and come in 12 ft lengths. For panels with battens like these, choose Battens only.
The Metric widths are examples, not a standard. The 70 mm batten is the actual width of a 25 × 75 mm planed batten at UK merchant Jewson, and the 150 mm board is from Scottish Wood's batten on board cladding, which uses 50 mm battens. Enter the width of the timber you have.
Space between boards
The gap lets wood boards move. The Western Red Cedar Lumber Association spaces boards 1/2 in apart, and Bob Vila uses 1/4 in. Bob Vila says each batten should overlap the boards on both sides by at least 1/2 in, and the association asks for at least 1/2 in with 6 in boards and more with wider ones. A 2 1/2 in batten over a 1/2 in gap overlaps each board by 1 in. The calculator only checks that the gap is narrower than the batten, so use the gap in your product's installation instructions.
Stock lengths and waste
The stock lengths start at 8 ft (2.4 m), the shortest length in the sources, such as 1x3 boards sold in 8 ft lengths and Scottish Wood's 2.4, 3.6, and 4.8 m lengths. Enter a length that fits your wall height, such as 10 ft for a 9 ft wall. The 10% waste allowance follows CertainTeed's siding estimating guide, whose formulas apply to vertical siding too. It covers split or warped pieces, miscuts, and offcuts too short to use.
Examples
A 12 ft accent wall
An 8 ft wall, 12 ft long, with 2 1/2 in battens up to 12 in apart gets 11 battens, 11 5/8 in apart and 14 1/8 in on center. Add 2 horizontal rows and the battens come to 112 ft, or 123.2 ft with 10% waste. That's 16 battens of 8 ft, $152.00 at $9.50 each.
Board and batten siding
A 20 ft wall, 8 ft tall, with 1x10 boards (9 1/4 in) 1/2 in apart needs 25 boards and 24 battens, 9 3/4 in on center. With 10% waste, buy 28 boards and 27 battens of 8 ft. At $18.00 per board and $6.50 per batten, the cost is $679.50.
A Metric wall
A 3.6 m wall, 2.4 m tall, with 70 mm battens up to 300 mm apart gets 11 battens, 283 mm apart and 353 mm on center. With 10% waste, that's 29.04 m, or 13 lengths of 2.4 m.
A square grid
For a grid of squares, choose rows so the squares are about as tall as the on-center spacing. Divide the wall height by the on-center spacing in the Layout table, round, and subtract 1. For an 8 ft (96 in) wall at 14 1/8 in on center, 96 ÷ 14 1/8 = 6.8, about 7 squares, so enter 6 horizontal rows.
FAQ
For a 12 ft wall with 2 1/2 in battens and up to 12 in between them, 11: (144 + 12) ÷ (2.5 + 12) = 10.76, rounded up. Add battens for each other wall and for any horizontal rows, and a waste allowance.
It's a matter of looks, so pick a space and split the wall evenly. Closer battens look more textured. On old board and batten walls, the batten spacing was the board width, and 1x3 battens over 1x10 boards sit 9 3/4 in on center. On exterior panels, battens are often set at 16 or 24 in on center to land on the studs.
Start at the center of the wall so the boards at both ends are ripped to the same width. If the end boards come out very narrow, center a gap on the wall instead of a board, which changes both end boards by half the on-center spacing (half a board width plus half a gap). Starting from the center can take one more board per wall than the calculator counts, which the waste allowance usually covers. Nail each batten through the gap between the boards, one nail at each support.
For a 20 ft wall with 9 1/4 in boards 1/2 in apart, 25 boards and 24 battens. With 10% waste and an 8 ft wall, buy 28 boards and 27 battens of 8 ft.
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