Calculate First Pass Yield
Enter your production volume and good units to calculate FPY. Toggle multi-step mode to calculate rolled throughput yield across your entire process.
Single-Step Yield
Multi-Step Process (RTY)
FPY = 920 / 1000 = 92.0%
First Pass Yield
92.0%
Good
FPY
92.0%
Defect Rate
8.0%
Units Rework
80
Yield Visualization
95%+
Excellent
85-95%
Good
70-85%
Fair
<70%
Needs Work
FPY Formula
First pass yield measures the percentage of units that pass through a process step correctly the first time, without any rework, repair, or rejection.
FPY = (Good Units / Total Units) x 100
RTY = FPY₁ x FPY₂ x ... x FPYₙ
Worked Example
A machining cell produces 500 parts per shift. After inspection, 465 parts pass without needing rework.
FPY Calculation
93.0%
465 / 500 = 93.0%
Impact
35 units
Required rework or were scrapped, consuming additional time and resources
Single-Step vs Multi-Step Yield
Single-step FPY measures one operation. Rolled throughput yield reveals the compounding effect of imperfect steps across an entire process.
Single-Step FPY
- •Measures one operation or workstation
- •Good for identifying problem areas in a specific step
- •Does not account for cumulative losses across the process
Rolled Throughput Yield (RTY)
- •Multiplies FPY across all process steps
- •Shows the true probability of a defect-free unit
- •Reveals hidden factory losses that final yield masks
Example: A 4-step process with 98%, 95%, 97%, and 99% FPY at each step produces an RTY of just 89.4%. That means roughly 1 in 10 units required rework somewhere in the process, even though each individual step looks healthy.
Improving First Pass Yield
Raising FPY requires addressing root causes of defects systematically rather than catching them at the end of the line.
Process Controls
- 1.Implement SPC charting on critical dimensions
- 2.Use poka-yoke to prevent errors at the source
- 3.Standardize setup procedures with documented work instructions
- 4.Conduct first-piece inspection on every job changeover
Root Cause Analysis
- 1.Pareto-chart defect types to find the vital few causes
- 2.Apply 5 Whys or fishbone diagrams on top defects
- 3.Track defect trends over time to verify corrective actions
- 4.Review operator training gaps tied to recurring failures