First Pass Yield
Personalize This
Get insights for your role
First Pass Yield (FPY) is the percentage of units that complete a process step correctly the first time without rework, repair, or rejection.
Definition
First Pass Yield (FPY) is the percentage of units that successfully complete a process step without requiring any rework, repair, or scrap. It measures right-first-time quality at a single process step. Unlike final yield, which counts units that eventually pass (including after rework), FPY captures only those that pass on their first attempt. FPY is a building block for Rolled Throughput Yield and reveals process quality more accurately than metrics that hide rework.
Examples
An assembly station processes 100 units per hour. 8 require touchup, 2 go to repair, and 90 pass without intervention. FPY = 90/100 = 90%. Even though all 100 eventually ship (100% final yield), FPY reveals that 10% require extra handling.
Key Points
- FPY = (Units passing first time) / (Total units processed) × 100%
- Does not include units that passed after rework, repair, or retesting
- FPY for multiple steps multiplied together gives Rolled Throughput Yield
- More accurate quality indicator than final yield metrics
Common Misconceptions
FPY and yield are the same. Traditional yield counts everything that eventually passes, hiding rework. FPY is stricter—only counting first-time success. A step might have 99% yield but only 85% FPY due to rework loops.
100% FPY is the goal. While high FPY is desirable, the optimal target depends on economics. If rework cost is low and prevention cost is high, 95% FPY might be economically optimal. Context determines appropriate targets.