Electronics Manufacturing worked example

First Pass Test Yield at 99% target first-pass test yield: a worked example

Push target first-pass test yield up to 99% and the picture changes. This example computes every intermediate figure at that operating point. a quality engineer is reviewing test yield for a board family, product, or line

The inputs for this scenario

  • Units passing first-pass test: 1,110 assemblies (unchanged)
  • Total units tested: 1,200 assemblies (unchanged)
  • Target first-pass test yield: 99 % (raised for this scenario; the documented default is 97)

Working through the calculation

  • Applying the documented formula (First-pass test yield = units passing first-pass test รท total units tested) to the inputs above produces each figure below.
  • At this operating point the engine returns 92.5 % yield for first-pass test yield, the number this scenario is built around.
  • At this operating point the engine returns 6.5 points for yield gap to target.
  • At this operating point the engine returns 1,110 assemblies for units passing first-pass test.
  • At this operating point the engine returns 1,200 assemblies for total units tested.

How this compares with the baseline

  • Against the tool's baseline example, where target first-pass test yield sits at 97% and the headline result is 92.5 % yield, this scenario lands almost exactly on the baseline at 92.5 % yield.
  • It computes the fraction of tested assemblies that pass on their first test attempt, plus the gap in points to your target FPY. 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

  • First-pass test yield: 92.5 % yield (headline result)
  • Yield gap to target: 6.5 points
  • Units passing first-pass test: 1,110 assemblies
  • Total units tested: 1,200 assemblies

Run it with your numbers

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

Last reviewed 2026-05-12.