Sheet utilisation: Sheet utilisation is the percentage of a sheet's area that ends up as parts after nesting, with the rest left as skeleton and offcuts.
After cutting, a sheet leaves parts and a skeleton. Utilisation is the area of the parts divided by the area of the sheet. Rectangular parts nest well; round or L-shaped parts leave gaps. Spacing for the kerf, margins at the sheet edges and grain direction rules all lower it. Remnants large enough to reuse can go back into stock and be partly credited.
What it means for the price
If material is charged by the area of each part, that charge must be divided by the expected utilisation so the whole sheet is paid for. A shop that assumes a high utilisation when it really achieves a much lower one under-recovers material on every job. The figure is best taken from the shop’s own nests over recent jobs, for each material.
Example: if parts are charged by area and utilisation is 70%, the true material cost per part is its area cost divided by 0.7, about 43% more. The figures are an example.
Common confusions
Sheet utilisation is not machine utilisation, which is the share of time a machine is busy. And a high utilisation on one nest says little about the average across jobs. Read nesting and material utilisation.
Go deeper: Nesting and material utilisation: how much of the sheet you really sell