Eyewear, Lenses & Vision Products worked example

Lens Blank Yield at 99% target first-pass blank yield: a worked example

Push target first-pass blank yield up to 99% and the picture changes. This example computes every intermediate figure at that operating point. a lens lab or procurement manager needs to track usable blanks versus blanks issued

The inputs for this scenario

  • Usable lens blanks after processing: 930 blanks (unchanged)
  • Lens blanks issued to production: 1,000 blanks (unchanged)
  • Target first-pass blank yield: 99 % (raised for this scenario; the documented default is 96)

Working through the calculation

  • Applying the documented formula (Lens blank yield = usable lens blanks after processing ÷ lens blanks issued to production × 100) to the inputs above produces each figure below.
  • At this operating point the engine returns 93 % for lens blank yield, the number this scenario is built around.
  • At this operating point the engine returns 6 points for yield shortfall to target.
  • At this operating point the engine returns 930 blanks for usable lens blanks after processing.
  • At this operating point the engine returns 1,000 blanks for lens blanks issued to production.

How this compares with the baseline

  • Against the tool's baseline example, where target first-pass blank yield sits at 96% and the headline result is 93 %, this scenario lands almost exactly on the baseline at 93 %.
  • It computes first-pass blank yield as usable blanks divided by blanks issued, and the point shortfall versus your target yield. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Lens blank yield: 93 % (headline result)
  • Yield shortfall to target: 6 points
  • Usable lens blanks after processing: 930 blanks
  • Lens blanks issued to production: 1,000 blanks

Run it with your numbers

  • Every input above is editable in the live Lens Blank Yield calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.