What packing method does this use?

It uses a first-fit-decreasing-height shelf heuristic, a well-known approximation for guillotine cutting. Parts are sorted tallest first and dropped onto horizontal shelves across each sheet, opening new shelves and new sheets only when needed.

Is the result the absolute minimum number of sheets?

Not always. Optimal 2D bin packing is computationally hard, so this gives a fast, realistic, near-optimal layout. An experienced cut planner working by hand may occasionally fit parts onto fewer sheets for tricky part mixes.

How does saw kerf affect the count?

Every cut removes a strip of material equal to the blade width. The tool inflates each part by the kerf on both dimensions so the layout reserves room for the saw, which prevents parts coming out undersized.

Can parts be rotated?

Yes. The packer tries each part in both orientations and marks any rotated part with a turn symbol on the diagram. This usually improves utilization, though for grain-matched faces you may want to disable rotation by entering parts at a fixed orientation.

What if a part is bigger than the sheet?

Any part that will not fit on the chosen sheet even when rotated is reported separately as unplaceable. Choose a larger sheet, split the part into joinable pieces, or order oversized stock for those parts.

What is the Plywood Sheet Optimizer?

Takes a list of rectangular parts as width by height by quantity and estimates the minimum number of 4x8, 5x5, or 4x4 sheets needed using a greedy 2D shelf bin-packing heuristic. Shows an SVG cut diagram for each sheet and accounts for saw kerf. It runs free in your browser on Gera Tools, with nothing uploaded.

Plywood Sheet Optimizer

Name: Plywood Sheet Optimizer
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Sheet goods are expensive, and a careless cut order wastes both material and money. This optimizer takes your list of rectangular parts and packs them onto the fewest sheets it can, showing a cut diagram for each one so you can take it straight to the saw.

How it works

The tool uses a first-fit-decreasing-height shelf algorithm, a standard heuristic for guillotine cutting:

1. expand every part by its quantity into individual rectangles
2. add the saw kerf to each rectangle's width and height
3. sort rectangles tallest first
4. place each on the first shelf where it fits, rotating if that helps
5. open a new shelf, then a new sheet, only when nothing else fits

Material utilization is the total area of your parts divided by the total area of the sheets used, so you can see how much offcut a given layout leaves behind.

Worked example

Suppose you are building a simple bookcase with:

2 side panels: 12 in × 72 in
3 shelves: 12 in × 36 in
1 top: 12 in × 36 in
1 back panel: 36 in × 72 in

With a 1/8 inch kerf and a standard 4×8 (48 in × 96 in) sheet, the optimizer places the back panel and one side panel on the first sheet, and the remaining side plus three shelves and the top on the second sheet — achieving roughly 78–82% utilization. Without sorting, a naive cut order might require a third sheet.

Saw kerf: why it matters more than people expect

A 1/8 inch (3.2 mm) table-saw blade removes material on every cut. On a part that requires six cuts from a sheet, that is already 3/4 inch of lost material — enough to push a borderline layout onto an extra sheet. The optimizer adds the kerf to every part dimension before packing so the reserved saw lane is always accounted for.

Standard sheet sizes

Sheet	Width	Length	Common use
4×8	48 in	96 in	Standard plywood, MDF, melamine
5×5	60 in	60 in	Marine and specialty ply
4×4	48 in	48 in	Half-sheet stock, small projects

Some suppliers also stock 4×10 or 5×10 sheets for large face panels — enter a custom size if the tool supports it, or split the part into joinable pieces.

Grain direction and rotation

The packer tries both orientations of each part and rotates when it saves space. For painted or structural parts this is usually fine. For veneered or grain- matched panels, you typically want the long dimension to run the same direction on all pieces — avoid rotated placements for those parts by entering them at a fixed orientation and accepting the extra offcut.

Reading the utilization number

Utilization below 60% is a signal to reconsider your sheet size or part grouping. Batching parts of similar heights onto the same sheet and cutting your longest strips first are the two biggest levers. Keep labeled offcuts: a 12×24 offcut from job A can often fill a small part on job B without buying another sheet.