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 11, 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.

Your measurements

One wall: area is wall length times height, minus each door and window.

Wall lengthftTotal length of all walls to be sided. For a gable end, add half the gable rise to the wall height so the triangle is counted.Wall heightftEach board and batten is cut to this length. Cedar 1x12 is stocked to 12 or 16 ft depending on the yard; taller walls get a horizontal break with Z-flashing or a special order.Openings to deductsq ftTotal area of doors and windows; a standard door is about 20 sq ft, a window 12 to 15. Skip openings under about 10 sq ft; the cutoffs are scrap.Board widthin11.25 in is the actual width of a 1x12; 9.25 in for a 1x10, 7.25 in for a 1x8. Rough-sawn cedar often runs full width, so measure a board from the lot.Batten widthin2.5 in is the actual width of a 1x3; 1.5 in for a 1x2, 3.5 in for a 1x4. 1x3 is the minimum on boards over 8 in once shrinkage is figured.Gap between boardsin1/2 in for kiln-dried boards. Green rough-sawn boards shrink 1/8 to 3/16 in per edge as they dry, so start them at 3/8 in. The batten must overlap each board edge by at least 1/2 in.Waste allowance%10% for straight walls with kiln-dried stock. 15% for gable ends, where every board is cut to the rake, and for rough-sawn bundles with wane.

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Boards46 boardsAll results

Results

Boards: 46 boards; 41 boards 11.25 in wide with 0.5 in gaps cover 40 ft, plus 10% waste; each cut to the full 9 ft
Battens: 47 battens; One more than the boards before waste, 2.5 in wide, centered over every gap and lapping each board by 1 in
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. Ring-shank siding nails, 8d for boards and 10d for battens; 304 stainless on cedar, hot-dipped galvanized on pine

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 wane, 15 on gable ends where every board is cut to the rake.

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, and 1x10 with 1x3 reads finer. Leave a 1/2 inch gap between kiln-dried boards, 3/8 inch for green rough-sawn stock, which shrinks 1/8 to 3/16 inch per edge as it dries. The batten has to lap each board by 1/2 inch after that shrinkage, which rules out 1x2 battens on boards over 8 inches.

Nail to blocking or nailers no more than 24 inches apart with 304 stainless ring-shank nails on cedar, hot-dipped galvanized on pine. Use 8d for the boards and 10d for the battens, which bridge the board thickness. Wide boards take two nails per row 3 to 4 inches apart at the center; battens take one nail per row through the gap so nothing pins two boards together. Back prime all six sides and every cut end with an oil or tannin-blocking primer before hanging.

What this calculator leaves out

Not counted: the house wrap R703.2 requires under any siding, 2x4 blocking between studs at 24 inches or a rainscreen mat, Z-flashing over openings and at horizontal breaks, corner boards and trim. Horizontal furring outside the wrap dams water behind vertical siding; use blocking in the wall, a rainscreen mat or crossed furring. Hold the bottom ends 1/2 inch above the drip cap and 6 inches above grade (R317.1).

Mistakes that cost money

Nailing battens through both board edges pins the boards and splits them as they dry; the batten nail goes through the gap only.
Electroplated or bright nails bleed black streaks down cedar within a season; use 304 stainless ring-shank, or hot-dipped galvanized on pine.
1x2 battens over a 1/2 in gap overlap only 1/2 in per side; green 1x12s shrink 3/16 in per edge, so use 1x3.
Skipping back priming lets the boards cup and the paint peel from behind; prime all six sides and every cut end before hanging.
Horizontal furring strips outside the house wrap dam water that gets behind vertical siding; use blocking inside the wall, a rainscreen mat or crossed furring.
Boards butted tight to the drip cap or ground wick water and rot; hold them 1/2 in off flashing and 6 in above grade (R317.1).

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 with 1x3 gives a narrower pattern, and 1x8 works for small walls and gables. 1x2 battens lap a 1/2 in gap by only 1/2 in per side and open up once green boards shrink, so keep them for 1x6 and 1x8.

Do I need house wrap and furring under board and batten?

Yes to house wrap; IRC R703.2 requires a water-resistive barrier under any siding. Vertical boards also need something horizontal to nail to every 24 in: 2x4 blocking between the studs is cleanest. Horizontal furring strips outside the wrap trap water, so if you want a drained cavity use a rainscreen mat or crossed furring, vertical strips first and horizontal over them.

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.