Shiplap Calculator
Enter a wall's width and height, the exposed width of your boards and their length to get the boards for the wall, counted by rows and by area, rounded up once.
Estimates for planning, not professional advice. Read the full notice.
Example: an accent wall
22 boards
- Rows up the wall 20 rows
- Boards counted by rows, with waste 22 boards
- Boards counted by area, with waste 22 boards
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Your project
Enter a size to see your total.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
Shopping list
| Item | Size | Buy |
|---|---|---|
| Shiplap boards | boards | 22 |
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Worked example: an accent wall
Show the working
- Rows: the wall height over the exposed width, rounded up 8 ft ÷ 5 in = 20 rows
- Boards for the rows: one board of this length spans the wall 20 rows × 1 board a row = 20 boards
- Add the waste allowance, once, and round up once 20 boards + 10 % waste = 22 boards
Assumptions
The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.
| Assumption | Value | Details and changes |
|---|---|---|
| Waste allowance | 10% | |
| Default An example allowance for cuts and breakage, added once. Change it for your own job. | ||
| Exposed width of a board | No default | |
| Default The width that shows once the board is fixed, from your own boards. It is a field above the result. Check your label or supplier. | ||
| Length of a board | No default | |
| Default From your own boards. It is a field above the result. Check your label or supplier. | ||
Feet and inches, like 12' 6"
Boards by exposed width
Rows and boards for the example wall at different exposed widths, with and without the waste allowance
| Exposed width | Rows | Boards, no waste | Boards, with waste |
|---|---|---|---|
| 3 in | 32 | 32 | 36 |
| 4 in | 24 | 24 | 27 |
| 5 in | 20 | 20 | 22 |
| 6 in | 16 | 16 | 18 |
| 8 in | 12 | 12 | 14 |
The wall and the boards are the worked example's. A narrower exposure means more rows, and each row is one board when the board is as long as the wall.
Questions
How many boards of shiplap do I need for a wall?
Enter the wall's width and height, the exposed width and the length of your boards. The calculator counts the rows up the wall, cuts each row from boards of your length, adds your waste allowance once and rounds up once. It also counts by area and gives the larger of the two.
Is the exposed width the same as the face width of the board?
No. The exposed width is the part that shows once the boards overlap, so it is narrower than the board's full width. Use the exposed width from your own boards.
What if a row is longer than one board?
The row is cut from several boards with butt joints and no overlap, and the calculator counts the boards needed for the joined row.