How Many Shiplap Boards Do I Need? (2026 Guide)
How many shiplap boards do I need? Divide the wall area by the coverage per board — a 1×6 covers 5.5 in of width, so a 12-ft board covers 5.5 sq ft — then add 10%: a 12×8 ft wall needs about 20 boards of 12 ft shiplap.
Shiplap coverage, step by step
We'll use a 12×8 ft wall (96 sq ft); the steps work for any rectangle.
1. Measure the wall in square feet
Multiply height by width: 12 × 8 = 96 sq ft, minus any full-height openings you won't cover.
2. Find the coverage per board
A 1×6 board is 5.5 in wide and the tongue-and-groove joint overlaps, so installed coverage stays about 5.5 in. Coverage per board = (coverage width ÷ 12) × board length: (5.5 ÷ 12) × 12 = 5.5 sq ft per 12-ft board.
3. Divide and round up
96 ÷ 5.5 ≈ 17.5 → 18 boards. Round up — you can't buy half a board, and the next board covers the partial run at the end of the wall.
4. Add 10% for waste
18 × 1.1 ≈ 20 boards. The shiplap calculator does the rounding for you.
Shiplap boards for common wall sizes
Counts assume 1×6 boards at 5.5 in of coverage and 12-ft boards (5.5 sq ft each). Base counts round up before the 10% waste is added:
| Wall size (ft) | Wall area | Boards, no waste | Boards, with 10% |
|---|---|---|---|
| 8 × 8 | 64 sq ft | 12 | 13 |
| 10 × 8 | 80 sq ft | 15 | 16 |
| 12 × 8 | 96 sq ft | 18 | 20 |
| 12 × 10 | 120 sq ft | 22 | 24 |
| 16 × 8 | 128 sq ft | 24 | 26 |
Read across: the 12×8 ft wall takes 18 boards before waste and 20 with 10%; the 16×8 ft wall scales up to 24 boards, 27 with waste.
Worked example: a 12×8 ft wall
Wall area: 12 × 8 = 96 sq ft. Each 12-ft 1×6 board covers (5.5 ÷ 12) × 12 = 5.5 sq ft, so 96 ÷ 5.5 ≈ 17.5 → 18 boards. Add 10%: 18 × 1.1 ≈ 20 boards. Using 8-ft boards instead? Each covers (5.5 ÷ 12) × 8 ≈ 3.7 sq ft, so the same wall needs about 30 boards of 8 ft.
Horizontal or vertical shiplap?
Horizontal boards run with the length of the wall, visually widen a room and waste the least. Vertical boards draw the eye up for hallways and accent walls, but each must span floor to ceiling, so measure that height before ordering. Either way, divide the wall area by the board's coverage and add 10%.
Installation tips that keep shiplap straight
- Deal with the wall first — remove baseboard and trim, patch holes, sand ridges and prime. Shiplap follows the framing, so a bowed wall gives you bowed lines.
- Nail or glue it — run a bead of construction adhesive on the studs, then pin each board through the tongue with 2-in finish nails so the next board hides them.
- Check level every few rows — walls drift, and staggered joints keep the seams from lining up into one long crack.
Measuring more of the room? The same measure, divide, round-up playbook covers baseboard for the room and the studs behind the wall.
FAQ
Is horizontal or vertical shiplap better?
Horizontal is the safer default — it runs with the wall's length, widens a room visually and wastes less on typical walls. Go vertical in hallways and accent walls to make the ceiling feel higher, but plan more waste for floor-to-ceiling cuts.
How much wall does a 1×6 shiplap board cover?
About 5.5 in of width. A nominal 1×6 is 5.5 in wide, and the tongue slips into the next board's groove, so installed coverage stays about 5.5 in — the calculator uses 5.5 in. A 12-ft board covers about 5.5 sq ft (5.5 ÷ 12 × 12).
Do I really need to add 10% for waste?
Yes. You lose material cutting ends, working around outlets, windows and doors, and on the odd miscut. Ten percent is about two extra boards on a 12×8 ft wall; skip it only on large plain walls.
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