First Pass Yield & RTY
First pass yield per process step and rolled throughput yield for the line from units started, failed and scrapped — with the rework that final yield hides.
FPY per step, cumulative and rolled throughput yield, final yield, good units out, total scrap and rework, and the step that caps the RTY — from the counts you enter.
Example: 1,000 units through cut (20 failed, 5 scrapped), weld (50, 10) and paint (30 reworked): FPY 98.0 / 95.0 / 97.0 %, RTY 90.2 %, but final yield 98.5 % — 85 units were reworked.
Yield that counts
the rework.
FPY and RTY, why final yield looks better, and what the counts mean.
FPY and RTY
First pass yield at a step = units passing inspection the first time ÷ units entering the step; rework counts as a failure. Rolled throughput yield multiplies the step FPYs in sequence — the chance that a unit gets through every step without rework or scrap. Units leaving a step are the passes plus the reworked units, since rework rejoins the flow; scrap leaves the line.
Final yield
Final yield = good units out ÷ units in. It is higher than RTY whenever anything is reworked, because rework hides the failures; the gap is the "hidden factory" — the reworked units the page counts. The step with the lowest FPY caps the RTY more than any other and is the first place to look.
What it assumes
Steps are treated as independent and the counts are the ones you enter for one period; nothing is forecast and no target is embedded. A unit reworked at a step is assumed to pass when it comes round again (its later failures would be in the next period’s counts). Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- FPY = units passing first time ÷ units entering; RTY = Π FPY over the steps in sequence; final yield = good units out ÷ units in — Six Sigma definitions, rework counted as a first-pass failure
Last reviewed 20 September 2026. How results are checked: How we verify.