How much material does nesting actually save? An honest answer.

Search this question and you get confident percentages, mostly from people selling nesting software. This page separates what is actually documented from what is marketing, and shows a small calculation you can redo with your own sheet price.

Where the headline percentages come from

The figure you see most often, 10 to 15 percent better yield for true-shape nesting compared with rectangular nesting, comes from Otimize, a nesting software vendor, on its own blog. CutPlan, an optimization vendor, claims cutting waste typically falls from 15 to 25 percent down to 5 to 12 percent with an optimizer. Xometry's editorial content speaks of 15 percent or more. None of these publishes the part sets or the method behind the number.

That does not make them lies. For the right geometry, those ranges are plausible. But they are claims made by parties selling the outcome, they are not reproducible, and your parts were not in the test. Read them as an upper expectation, not a promise.

Rectangular versus true-shape: what the terms mean

Rectangular (bounding-box) nesting treats every part as the smallest rectangle that contains it and packs the rectangles. True-shape nesting works with the actual outlines: concave parts interlock, L-shapes hook into each other, discs tuck into notches, and small parts can sit inside another part's cutout. The entire difference between the two methods is the empty air inside those bounding boxes.

Which leads to the sentence most vendors leave out: if your parts are rectangles, true-shape nesting gains you almost nothing. Cabinet panels, shelves, boxes: the bounding box is the part, there is no air to reclaim, and a guillotine cut-list optimizer already handles that job well. The gains appear when outlines are concave or curved, because that is where the boxes contain air: brackets, letters, cam profiles, curved blanks, garment shapes.

What actually moves the number

Geometry first, as above. After that: quantity and mix. More parts and varied sizes give the nester more combinations, and small parts plug the gaps between big ones. Rotation freedom matters too; a grain constraint on wood or brushed metal costs yield because parts lose orientations. So does the ratio of sheet size to part size: three large parts on one sheet leave little room for cleverness. And spacing overhead counts, because the generous distances a plasma table needs eat a share of the theoretical gain on small parts.

A worked example, labelled as such

The structure of the example matters more than its numbers: savings arrive as whole or partial sheets you do not buy, multiplied by your sheet price and your volume. A hobbyist cutting one sheet a month saves pocket money. A small shop cutting 40 sheets of birch ply or mild steel a month is looking at a real line item.

How to get your number instead of a claim

Count sheets for a real batch as you lay it out today: manual arrangement in CAD, LightBurn's array tools, whatever you actually use. Then nest the same parts with a true-shape nester and count again. Sheets saved times sheet price is your number, and it beats any percentage on a vendor page, including this one's examples. Use a deterministic tool for the comparison if you can, because same input plus same result means the number is reproducible instead of a lucky run.