Shiplap Calculator & Cut Planner
Place wall openings and chosen joints, inspect each shiplap row and get a feasible board cutting schedule.
WALL BOARDS · COURSE BY COURSE
Plan the wall. See every cut.
Place doors and windows, inspect each board row, and get a cuttable stock plan. Choose inches or millimetres; use actual board dimensions, not nominal sizes.
Your wall and boards
Rows overlap when the installed step is less than physical board width. The first board begins at the field edge. This tool plans square-cut blanks, not a machined tongue/groove profile.
Doors and windows
Measure from the bottom-left corner of the boarded field. Use the complete unboarded opening, including trim where appropriate. Openings may touch but must not overlap.
A partial-height cutout still needs a full-length blank. Cutouts and ripped strips are not reused as full-width stock.
Joints, reserve and price
Choose joint positions on suitable backing and check your product’s fastening and stagger rules. The planner does not approve mounting locations or scarf joints.
20 boards in the cut plan + 2 spare · 20 rows · 20 blanks.
Wall elevation
144 × 96 in · horizontal boards
To scale: visible row fields and unboarded openings. Select a row on the diagram or below. Hidden overlap is included in the cutout schedule.
Row 1: one 144 × 5.5 in blank. Stock board 1.
Projected edge width is not a finished profile rip dimension. Check tongues, grooves, end clearances and any slender remaining material before cutting.
Stock cutting plan
20 stock boards, each used at its full 144 in length; no crosscut kerf or end offcut. Two extra boards are separate reserve.
Every blank is assigned to a stock board. This is a feasible best-fit plan, not a guarantee of the fewest boards. All stock is the same material, profile and usable length.
Show stock cuts and offcuts
How the calculation works
The first blank covers its actual board width. Each next blank begins one installed step later. The last board is cropped at the field edge. Openings crossing the entire physical blank width split it into shorter blanks. Partial cutouts retain that blank’s full length.
Selected joints split those blanks before packing. Longest blanks are placed first into the tightest remaining stock length. Each separating crosscut consumes kerf; a last sliver shorter than the kerf is discarded completely. Ripped strips and internal cutouts are excluded from stock reuse. Extra boards are rounded up separately.
The model uses up to 300 rows, 20 openings and 2500 blanks. It does not model defects, curved cuts, tool access, joint gaps, scarf allowances, fastening, moisture suitability, structural loads or a product-specific profile. Use the manufacturer’s instructions to choose clearances, backing and joints.
Kebony’s installation guide illustrates why joints need verified backing and edge cuts need profile checks; its exterior-product rules are not defaults for interior shiplap. Dakota’s interior guide separately plans edge ripping and a dry layout for its own board-and-batten products.
For vertical decorative battens with equal spacing, use the board and batten calculator. For rectangular plywood panels, use the sheet cut list optimizer.
