Board and Batten Calculator

Calculate how many boards, battens, linear feet of lumber and nails you need for board and batten siding on a wall, with openings deducted and waste added.

By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.

Quick answer: To estimate board and batten siding, divide the wall length in inches by the board width plus the gap and round up for boards, add waste, and count one more batten than boards. A 40 ft wall 9 ft tall with 1x12 boards, 1x3 battens and 1/2 in gaps needs 46 boards and 47 battens, about 345 ft of boards once 60 sq ft of openings are deducted.

Results

Boards: 46 boards; 41 boards 11.25 in wide with 0.5 in gaps cover 40 ft, plus 10% waste; each 9 ft long
Battens: 47 battens; One more than the boards before waste, 2.5 in wide, centered over every gap
Board lumber: 345 ft; Total length after deducting 60 sq ft of openings from 360 sq ft of wall
Batten lumber: 353 ft; Same deduction applied; buy the battens in the wall height too
Nails: 695 nails; 2 per board and 1 per batten at each of 5 nailing rows 24 in apart; 8d ring-shank siding nails

Board and Batten formula

Boards = Wall length (in) / (board width + gap), rounded up, x (1 + waste %)
Battens = (Boards before waste + 1) x (1 + waste %)
Board linear ft = Boards x wall height x (wall area - openings) / wall area
Nails = (2 per board + 1 per batten) x nailing rows at 24 in

Worked example

A 24 ft gable-end wall 10 ft tall with 1x10 boards (9.25 in), 1x2 battens (1.5 in), 1/2 in gaps, 20 sq ft of window and 10% waste: 24 x 12 / (9.25 + 0.5) = 29.5, so 30 boards, or 33 with waste. Battens: 31 x 1.1 = 34.1, so 35.

The wall is 240 sq ft and the window takes 20, so 220 / 240 of each board is needed: 33 x 10 x 220 / 240 = 302.5 ft of boards and 35 x 10 x 220 / 240 = 320.8 ft of battens. Nailing rows: 10 x 12 / 24 = 5, so 33 x 2 x 5 + 35 x 5 = 505 nails.

Quick reference

Boards and battens per 100 ft of wall by board size (1/2 in gap, 10% waste)
Board	Actual width	Boards	Battens
1x6	5.5 in	220	222
1x8	7.25 in	171	172
1x10	9.25 in	137	138
1x12	11.25 in	114	115

How to estimate board and batten

Each board plus one gap is one repeat, so the wall length in inches divided by the board width plus the gap gives the number of boards. Battens cover the gaps, and there is one more gap than boards when the run starts and ends with a batten at the corners. Add 10 percent for cuts and rejects, more on walls with many windows.

Every board and batten is cut to the full wall height, so linear feet are simply the count times the height. Openings are deducted from the linear feet rather than the count, because the pieces above and below a window still have to come from full-length stock unless you plan the layout carefully.

Materials and installation

Rough-sawn cedar, pine and fiber cement are the usual choices; 1x12 boards with 1x3 battens are the classic proportion, while 1x10 with 1x2 reads finer. Leave a 1/2 in gap between boards so they can move with the seasons, and make sure the batten overlaps each board by at least 1/2 in.

Nail boards to blocking or nailers no more than 24 in apart with ring-shank siding nails long enough to penetrate the framing by 1-1/2 in. Wide boards take two nails per row about a third of the way in from each edge; battens take one nail per row driven through the gap so it does not pin the boards. Prime all six sides before installing, including the cut ends.

Key facts

A nominal 1x12 board is actually 3/4 x 11-1/4 in, and a 1x3 batten is 3/4 x 2-1/2 in.
Reverse board and batten puts the narrow battens underneath and the wide boards on top, so the gaps between boards show a recessed batten.
Battens must overlap each board edge by at least 1/2 in; a 1/2 in gap under a 2-1/2 in batten gives 1 in of overlap per side.
Vertical siding over studs needs horizontal blocking or nailers, typically 24 in apart, so every board and batten has something to nail to.
Boards over 6 in wide get two nails per row, and the batten nail goes through the gap between boards so both can shrink and swell.

Frequently asked questions

How many boards do I need for board and batten?

Divide the wall length in inches by the board width plus the gap and round up, then add 10% waste. A 40 ft wall with 1x12 boards and 1/2 in gaps needs 41 boards, or 46 with waste, and 47 battens.

What size boards and battens should I use?

1x12 boards (11-1/4 in actual) with 1x3 battens (2-1/2 in) are the traditional pairing. 1x10 boards with 1x2 battens give a narrower pattern, and 1x8 works for small walls and gables.

How much gap should be left between boards?

About 1/2 in, so the boards can shrink and swell without splitting. The batten needs to overlap each board by at least 1/2 in, so a 1x3 batten easily covers a 1/2 in gap.

What is reverse board and batten?

The battens go on first against the wall and the wide boards go over them with a gap that shows the batten underneath. Counts are the same; only the order of installation changes.

Sources and references

Western Red Cedar Board & Batten Siding (sizes and coverage) (Western Red Cedar Lumber Association)
Western Red Cedar siding installation guide (Western Red Cedar Lumber Association)
Chapter 7 Wall Covering, 2021 IRC (R703.3 siding attachment) (ICC)

Next steps for this project

The usual order for a framing, decks & fences project. See all framing, decks & fences calculators.

Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.