Yield Analysis Calculator

FPY and RTY are mathematically identical when every stage is treated as an independent one-pass step, which is what this calculator assumes: it multiplies Stage1% × Stage2% × Stage3% × Stage4% for both figures. They diverge in real factories when a stage has internal rework loops that let a unit be inspected and reworked multiple times before moving on — a scenario this tool doesn't model, since it just walks units forward through four sequential stages.

Hidden Factory % is defined here as the gap between a naive traditional yield (final good units divided by total input) and RTY. Because this calculator's stages are independent with no rework, and both figures are derived the same way from the same stage percentages, that gap collapses to essentially zero — only rounding noise remains. The classic hidden-factory concept, the extra labor and time consumed by inspection and rework loops, would only show up as a real gap if the model tracked units cycling back through a stage instead of exiting the process on failure.

It simply compares the four stage yield percentages you entered and flags whichever one is lowest — it doesn't weight by unit volume or defect count, just the percentage itself. Because yields compound multiplicatively across stages, the weakest single stage is usually the highest-leverage place to focus improvement, since even a small yield loss there pulls down every unit that has already survived the earlier stages.

The calculator rounds the surviving unit count after each stage so the per-stage table reports whole, physically meaningful units rather than fractional ones. This means the reported stage-by-stage defect counts can differ very slightly from what you'd get by applying the overall yield percentage to the total in one step, though the difference is only ever a rounding artifact of a unit or two per stage.