Estimate only. Shiplap and tongue-and-groove boards cover less than their nominal width, so use the covering width on the label.
How to use this calculator
Enter the wall length and the height you want to cover, then the board width and length. Press Calculate to see how many boards you need for shiplap, wainscoting or wall panels. Add a price to get the cost.
The formula
Wall area = length × height
Coverage per board = board width (in) ÷ 12 × board length (ft)
Boards = area × (1 + waste) ÷ coverage per board
Example: A wall 12 ft long and 8 ft high is 96 sq ft. Boards 5.5 in wide and 8 ft long cover 3.67 sq ft each, so with 10% waste you need 29 boards.
Getting your wall panel estimate right
The calculator finds the wall area, works out how much one board covers and divides one by the other. It then adds your waste allowance and rounds up to whole boards. The result is the number of boards to buy for shiplap, tongue and groove, beadboard planks or similar panels.
A worked example
A 12 foot wall paneled 8 feet high is 96 square feet. A board 5.5 inches wide and 8 feet long covers about 3.67 square feet. With 10% waste, the wall needs 29 boards. If you only panel the lower part of the wall to 3 feet high, the area drops to 36 square feet and the count falls to about 11 boards.
What changes the board count
- Covering width. Shiplap and tongue and groove overlap, so a board sold as 6 inches may cover only about 5 to 5.5 inches. Always enter the covering width.
- Board length. Boards that are shorter than the wall mean more end joints and more offcuts.
- Pattern. Vertical and horizontal installs use similar amounts. Diagonal and herringbone patterns waste more, so use 15%.
- Openings and outlets. Windows, doors and switch boxes all need cuts that can turn a full board into scrap.
Tips and common mistakes
- Let wood boards sit in the room for a few days before installing so they adjust to its humidity.
- Find and mark the studs first. Nail into studs, or use adhesive where the product allows it.
- Start from a level line, not the floor or ceiling, which are rarely perfectly straight.
- Stagger end joints on long walls so seams do not line up in a visible pattern.
- Use spacers, such as a nickel or a shim, to keep the gaps even on shiplap.
- Turn off power before removing outlet covers, and use box extenders if the panels move the outlet face out.
Buying and cost
Enter the price per board to see the material cost. Buy all boards from the same batch when you can, since color and thickness can vary between lots. Add the cost of trim, nails, adhesive, caulk, wood filler and paint or stain. Primed MDF boards are often cheaper and more stable than solid wood but usually do not suit damp areas. For bathrooms, look for moisture-resistant or PVC panels. Keep a few spare boards for future repairs.

