Plate utilisation calculator
Estimate how many cut pieces fit on a plate, how many plates you need for your quantity and how much waste occurs. Simple grid packing as quick material planning — for optimal nesting, a nesting software is recommended.
Note: All values are non-binding reference figures. Actual values depend on machine, tool, material and conditions. Start conservatively. No liability is accepted for tool breakage, machine damage or machining results.
What the Sheet Utilisation Calculator Works Out
The calculator estimates how many equally sized pieces fit on a sheet, how many sheets you need for your quantity, and what the waste percentage is. It automatically checks both orientations (the piece as is and rotated by 90°) and selects the option that yields more parts per sheet.
The Formula
Per row, as many parts fit as the piece length (plus the cutting kerf) divides into the sheet length (plus the cutting kerf), rounded down to whole pieces:
Parts per row = ⌊(Lsheet + K) / (Lpiece + K)⌋
The same applies to the number of rows using the width. Parts per sheet is the product of the two, and the number of sheets required is the quantity divided by parts per sheet, rounded up. The waste is the difference between the utilised area and the total area of all required sheets.
What This Estimate Cannot Do
- No true nesting: The calculator works with a simple grid (all parts aligned identically). Nesting software can rotate parts differently and interlock them. With unequal edge lengths or irregular shapes, the real yield is often higher.
- Rectangular pieces only: For round, angled, or irregular shapes, the formula does not produce meaningful values.
- No allowance for sheet defects: Knots, damage, or grain direction (in wood-based materials) are not taken into account.
- Offcut reuse: Remnants that could still be useful for smaller follow-up jobs are not included in the waste calculation.
What the Estimate Is Suitable For
For a quick first material plan (how many sheets do I need to order, roughly what does the material cost?), the formula is a good guide, especially for uniform, rectangular pieces such as shelves, side panels or fascia panels. For complex mixes of cut pieces, or when every percentage point of waste matters, it is worth using real nesting software that plans the CAM toolpaths directly.
Frequently Asked Questions
Why does the real yield differ from the calculation?
The calculator uses a simple grid with uniform orientation. Real nesting software can rotate, mirror and interlock parts. With pieces of unequal edge lengths (e.g. long narrow strips), it is often possible to get more out of a sheet than with a simple grid.
What should I enter as the cutting kerf?
That depends on the tool: for a 6 mm milling cutter used for peripheral milling, the kerf is roughly the tool diameter; for a circular saw it is usually 3–4 mm. To be on the safe side, allow a slightly more generous kerf: it is better to plan for one extra sheet than to calculate too tightly.
Are offcuts included in the waste calculation?
No. The calculator shows the waste for the current order. Usable remnants for later, smaller jobs are not included. If you collect and reuse offcuts, the actual waste in practice is often lower.
Can I plan different piece sizes on one sheet with this?
No, the calculator assumes a single, uniform piece size per run. For a mix of different part sizes on the same sheet, you need real nesting software that optimises multiple shapes simultaneously.
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