🪵 Shiplap Calculator
Work out how many shiplap boards and how much linear footage you need to cover a wall, with a waste allowance included.
What this calculator does
The Shiplap Calculator estimates how many boards you need to cover a wall with shiplap siding or paneling, based on the wall’s dimensions and the exposed face width of each board.
The formula
The wall area is divided by the board’s exposed width to find how many linear feet of board are needed to fill every row from floor to ceiling: Rows = Wall height / Board face width, then Linear feet needed = Rows × Wall width. That figure is increased by your chosen waste percentage (to cover cut ends, mistakes, and pattern matching) and divided by the length of a single board to give the number of boards to buy.
Board feet (a common lumber-pricing unit) is also shown, based on nominal 1-inch-thick boards.
- Shiplap boards overlap slightly at their edges; enter the exposed face width after overlap, not the full board width, for an accurate count.
- Round up to the nearest whole board when ordering, and always keep a small waste margin for cutting around windows, doors, and outlets.