Shiplap Calculator
Enter the wall size and subtract windows and doors to get the linear feet of shiplap, how many boards to buy, the number of rows and, for DIY plywood shiplap, how many sheets to rip.
Shiplap for common wall sizes
Linear feet to buy, including 10% extra, with no windows or doors:
| Wall | Area | 1x6 shiplap | 1x8 shiplap |
|---|---|---|---|
| 8 × 8 ft | 64 sq ft | 165 ft | 123 ft |
| 10 × 8 ft | 80 sq ft | 207 ft | 154 ft |
| 12 × 8 ft | 96 sq ft | 248 ft | 185 ft |
| 14 × 8 ft | 112 sq ft | 289 ft | 216 ft |
| 12 × 9 ft | 108 sq ft | 279 ft | 208 ft |
| 16 × 9 ft | 144 sq ft | 371 ft | 277 ft |
How to calculate shiplap
- Measure the wall with a tape measure and multiply width × height for the area. Use the square footage calculator for odd shapes.
- Subtract openings: windows and doors, measured to the outside of their trim.
- Divide by the exposed width of one board (in feet) to get linear feet: 80 sq ft ÷ (5.125 ÷ 12) = 187 ft.
- Add 10–15% for cuts around outlets and windows and for boards with defects.
- Divide by the board length to get the number of boards.
Installation tips
- Start at the bottom (horizontal) with the tongue or lip facing up, level the first row and check every few rows.
- Use nickels as spacers for the classic gap; nail into studs, which are usually 16 in apart.
- Stagger the joints on long walls so seams don't line up from row to row.
- Paint the wall first in the shiplap color, so the gaps don't show the old color.
Frequently asked questions
How do I calculate how much shiplap I need?
Find the wall area in square inches (width × height), subtract windows and doors, and divide by the exposed width of one board to get the total length in inches; divide by 12 for linear feet and add 10% for cuts. A 10 × 8 ft wall in 1x6 shiplap (about 5⅛ in exposed) needs about 187 linear feet before waste.
How much does a 1x6 shiplap board cover?
A 1x6 board is 5½ inches wide, but the overlap (the rabbet) hides about ⅜ inch, so each row covers about 5⅛ inches. Exact coverage varies by brand and is printed on the label, so measure one board if you can.
How many rows of shiplap on an 8 ft wall?
About 19 rows of 1x6 shiplap (96 ÷ 5⅛ = 18.7, so the top row is ripped narrower), or 14 rows of 1x8. Many installers rip the first and last rows to about the same width so the wall looks balanced.
Can I make shiplap from plywood?
Yes. Rip ¼ in plywood or underlayment into 6 or 8 inch strips and nail them up with a nickel (about ⅛ in) spacer between rows. One 4 × 8 sheet gives seven 6-inch strips or five 8-inch strips after saw kerfs. It's cheaper than real shiplap but doesn't overlap, so paint the wall behind dark first.
Should shiplap go horizontal or vertical?
Horizontal shiplap makes a room feel wider and is the classic farmhouse look. Vertical makes ceilings look taller and suits small or narrow rooms. The amount of material is about the same either way.
Other wall treatments: the board and batten calculator and the wainscoting calculator.