First Pass Yield (FPY) is the share of units made right the first time, with no scrap and no rework. It is a cleaner quality measure than a simple pass rate because it penalises rework.
The First Pass Yield formula
First Pass Yield = (Total Units - Scrap - Rework) / Total Units
Step by step
- Count total units. Take the total units that entered the step or process.
- Count scrap and rework. Count units scrapped and units that needed rework (both fail first-time quality).
- Divide. FPY = (Total - Scrap - Rework) / Total, as a percentage.
- Roll up multi-step lines. For a whole line, multiply each step's FPY together to get Rolled Throughput Yield (RTY).
A worked example
A process ran 20,000 units, scrapped 500 and reworked 300:
| Step | Calculation | Result |
|---|---|---|
| Good first time | 20,000 - 800 | 19,200 |
| First pass yield | 19,200 / 20,000 | 96.0% |
| If 3 steps each 96% | .96 × .96 × .96 | 88.5% RTY |
Our free Scrap & Quality Cost Calculator does this live, with the benchmark overlay.
Common mistakes
- Counting reworked units as good (FPY must exclude them).
- Reporting only final yield, hiding the rework loop in the middle.
- Forgetting to multiply step yields for a true rolled throughput yield.
First Pass Yield FAQ
Why does FPY exclude rework?
Because rework still costs time and money even if the unit is eventually sold. FPY shows how often you got it right the first time.
What is rolled throughput yield?
RTY multiplies the FPY of every step in a line, showing the realistic chance a unit passes all steps with no rework.
How does FPY relate to OEE?
FPY is closely tied to the Quality factor of OEE, which counts only good first-time parts.
Related: scrap rate · OEE · root cause analysis