Guillotine Cutting Generator

What this generator does

Divides a sheet by repeatedly splitting a rectangle fully in two, either horizontally or vertically, until the requested number of pieces exists. Because every division is a full edge-to-edge cut, the resulting layout is guaranteed cuttable, and the cuts are listed in the order a saw would make them.

How to use this tool

1. Set the sheet size and how many pieces to divide it into.
2. Follow the cuts in order — each one splits a rectangle fully in two.
3. Notice that every piece is a rectangle, and every boundary runs the full width or height of its region.
4. Try to produce the same layout with a cut that stops halfway; you cannot.

Understanding the controls

Sheet width

The full width of the material before any cutting.

Sheet height

The full height of the material. A long thin sheet produces very different layouts from a square one.

How many pieces

Between 3 and 24. Dividing into n pieces always takes exactly n minus one cuts, whatever order they are made in.

Seed

Any word reproduces exactly the same cuts and the same layout.

Common use cases

• Planning cuts for sheet material — plywood, glass, board, metal
• Teaching the guillotine constraint and why it makes packing harder
• Generating cutting diagrams for a workshop exercise
• Test instances for a cutting-stock implementation
• Setting the same layout twice from a seed

How this generator works

Splitting recursively is what guarantees the constraint holds: a cut is applied to one rectangle and produces two, so no piece can ever be non-rectangular and no cut can ever need to stop partway. The check confirms the pieces tile the sheet exactly with no overlap and nothing left over, which is what a correct recursive division must produce.

Randomness and fairness

Where each cut falls, and whether it runs horizontally or vertically, are random; the constraint is guaranteed by construction. A seed reproduces the same layout exactly and is therefore explicitly not cryptographically secure. Without a seed the browser's cryptographically secure generator is used.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

• This divides a sheet freely rather than fitting a list of required sizes, which is the harder and more useful problem.
• No saw kerf is modelled, so the pieces tile the sheet exactly where a real cut would consume a few millimetres each time.
• Whole-number sizes only.
• Cuts are shown in the order generated, which is not necessarily the most convenient order to make them.
• Nothing about the arrangement is kept, so seed one worth cutting to.

Privacy and your data

The sheet and every cut are worked out on your own device. Neither the layout nor your seed is transmitted or stored.