Plywood Cut Calculator

How to use it: enter your sheet size and saw kerf, then add as many part rows as your cut list needs - each with its own width, height and quantity. Use Add part for another size and the button to remove a row (at least one row must remain). The layout, sheet count and waste percentage update immediately, and you can print or download the first sheet's diagram.

Algorithm. Every requested part (every row, every quantity) is combined into one list and sorted longest-edge-first. Each part is then placed left to right along a "shelf" (row): if it fits in the current row's remaining width it's placed next to the last part with one kerf gap between them; if not, a new row starts above the tallest part already in the current row, again separated by one kerf; if it doesn't fit in the sheet's remaining height either, a new sheet starts. A part is rotated 90° automatically if that's the only way it fits the sheet. Area waste is the unused fraction of total sheet area actually consumed: waste % = 100 × (sheets × sheet area − total part area) / (sheets × sheet area).

Worked example. With the default two-row list (2440×1220 mm sheet, 3 mm kerf, four 600×400 mm parts, six 300×300 mm parts): the four 600×400 parts are longest-edge first, so they're placed in a row along the bottom - four of them plus three 3 mm kerfs use 4×600 + 3×3 = 2409 mm of the 2440 mm width, all within the 400 mm row height. The fifth part (a 300×300) no longer fits that row's remaining width, so a new row starts at y = 400 + 3 = 403 mm; all six 300×300 parts fit across that row (6×300 + 5×3 = 1815 mm), and the whole layout - 703 mm tall - fits on a single 1220 mm-tall sheet. Result: 1 sheet, 10 parts placed, and area waste = 100 × (2440×1220 − (4×600×400 + 6×300×300)) / (2440×1220) = 100 × (2,976,800 − 1,500,000) / 2,976,800 ≈ 49.6% - most of it the unused 517 mm-tall strip above the two packed rows. Adding a third row (for example eight 150×150 mm offcuts) simply adds those parts to the same sorted list and packing pass - no separate run needed.

The layout comes from a longest-first shelf-packing heuristic, not a guaranteed-optimal nesting algorithm - it can leave more waste than a human or a true bin-packing solver would for the same parts. Always check the diagram against your actual sheet before cutting.

It does not model grain or face-veneer direction, does not reserve a trim margin around the sheet edge (kerf is only applied between parts), and assumes every part can be rotated 90° if that helps it fit. If any part is larger than the sheet in both orientations, no layout is returned. The parts list is capped at 12 rows in this interface to keep the layout readable and the page responsive.