Board and Batten Siding Calculator

A board and batten siding calculator returns the number of boards and battens for a wall. It divides wall length by board width plus gap, adds waste, and rounds up to whole boards. Battens equal the board count minus one. Boards and battens are cut to the full wall height.

Last reviewed September 2026Method & sources Report an error

Not to scale.

Boards Needed

Includes a 10% waste allowance.

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Boards23 boards (cut to wall height)
Battens22 battens (cut to wall height)

Breakdown
Boards Needed	23
Battens Needed	22
Total Board Length	230 ft
Total Batten Length	220 ft

How to Calculate Board and Batten Siding

Board pitch (board width plus the gap left between boards) divides into the wall's total length to give the raw board count. A waste allowance covers cutting and the occasional damaged board. The result then rounds up to a whole board. Boards are normally cut to the full wall height, so total board length is simply board count times height. Each gap between adjacent boards gets one batten strip covering the seam. With N boards installed, there are N−1 interior gaps, so battens needed is one fewer than the board count.

Example: 20 ft wall, 10 ft tall, 11.25 in. (1x12) boards, 0.5 in. gap

A 20 ft wall, 10 ft tall, 11.25 in. (1x12) boards, 0.5 in. gap, 10% waste: 1. Board pitch: 11.25 + 0.5 = 11.75 in. 2. Wall length: 20 × 12 = 240 in. 3. Raw boards: 240 ÷ 11.75 = 20.43 4. With 10% waste: 20.43 × 1.10 = 22.47, rounded up to 23 boards 5. Battens: 23 − 1 = 22 6. Total board length: 23 × 10 = 230 ft 7. Total batten length: 22 × 10 = 220 ft

Board and Batten Siding: Compare Scenarios

Scenario	Boards Needed	Battens Needed	Total Board Length	Total Batten Length
Small (10×8 ft accent wall)	12	11	96 ft	88 ft
Medium (20×10 ft wall)	23	22	230 ft	220 ft
Large (40×12 ft wall)	45	44	540 ft	528 ft

What Is Board and Batten Siding?

Board and batten is a siding style using wide vertical boards with a gap between them, covered by a narrower vertical strip (the batten) that seals the seam. This calculator converts a wall's length and height into the number of boards and battens needed, both cut to the full wall height as continuous pieces rather than joined stock lengths.

Board and Batten Siding: Pros and Cons

Pros

Models boards and battens as cut-to-height pieces, matching how board and batten siding is normally installed rather than assuming a shorter stock length needing joints
Battens are derived directly from the actual (waste-adjusted) board count, so the two figures always stay consistent with each other
Works for either standard 1x10 or 1x12 board widths, with an adjustable gap for different reveal styles

Cons

Doesn't include the corner trim or top/bottom trim boards that finish a board and batten wall's edges. Plan those separately.
Doesn't account for door and window openings. Subtract their width from the wall length, or treat the wall as multiple sections split by each opening.
Assumes battens run the same full height as the boards. A design with a shorter accent batten section would need its own separate calculation.

Board and Batten Siding: What a Pro Checks

Pick your gap width based on the batten that will cover it. The batten needs to overlap both board edges enough to seal the seam, so a wider gap calls for a wider batten.
Subtract door and window widths from the wall length first, or split the wall into separate sections at each opening. This estimate doesn't remove openings on its own.
Order corner trim and top and bottom trim boards as a separate line item. They finish the wall's edges but aren't part of this board and batten count.

Frequently Asked Questions

How many boards do I need for board and batten siding?

Divide the wall's length (in inches) by the board width plus your chosen gap, add a waste allowance, and round up. A 20 ft wall with 11.25 in. boards and a 0.5 in. gap needs about 23 boards.

How many battens do I need?

It's one fewer than the number of boards. Each batten covers the seam between two adjacent boards, so N boards create N−1 interior gaps, each needing a batten. 23 boards need 22 battens.

What size gap should I leave between boards?

A common range is about 1/4 in. to 1 in. The gap often depends on the batten's width and the overall look you're going for. The batten needs to overlap both board edges enough to seal the seam. A wider gap uses fewer boards but needs a wider batten to cover it properly.

What size boards are used for board and batten siding?

1x10 (actual 9.25 in.) and 1x12 (actual 11.25 in.) are the most common widths for the vertical field boards, with a narrower board (often 1x2 or 1x3) used for the battens covering the seams.

Do boards and battens need to be one continuous piece per wall height?

That's the most common installation, cutting each board and batten to the full wall height in one piece for a clean vertical line. A very tall wall exceeding available stock lengths would need a horizontal joint, which this calculator doesn't account for.

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