Enter Production and Quality Data
Example Data Table
Sample figures below demonstrate multi-step yield tracking for a single batch.
| Step | Input | First-Pass Good | Rework | Scrap | Defects | Step FPY |
|---|---|---|---|---|---|---|
| Assembly | 1000 | 960 | 25 | 15 | 40 | 96% |
| Inspection | 980 | 950 | 15 | 15 | 25 | 96.94% |
| Packaging | 970 | 945 | 10 | 15 | 20 | 97.42% |
Formula Used
- First Pass Yield (FPY) = First‑Pass Good Units ÷ Total Input Units
- FPY % = FPY × 100
- Step FPY = Step First‑Pass Good ÷ Step Input
- Rolled FPY = Π(Step FPY) across all valid steps
- Rework Rate = Reworked Units ÷ Total Input Units
- Scrap Rate = Scrapped Units ÷ Total Input Units
- DPMO = Defects ÷ (Total Input × Opportunities per Unit) × 1,000,000
- Sigma (approx.) = NORMSINV(1 − DPMO/1,000,000) + 1.5
- Cost of Poor Quality = (Reworked × Cost/Rework) + (Scrapped × Cost/Scrap) + (Defects × Cost/Defect)
How to Use This Calculator
- Enter the total units that entered your process scope.
- Enter units that passed without any rework as first-pass good.
- Add rework, scrap, and defects for deeper loss visibility.
- Set opportunities per unit if you track defect opportunities.
- Optionally add each process step to compute rolled FPY.
- Press Calculate to view results above the form.
- Use Download CSV or Download PDF to share results.
Operational meaning of first pass yield
First pass yield (FPY) shows how many units meet requirements without any rework. Track it by shift, product family, and line to separate true process capability from temporary firefighting. A stable FPY above 98% often signals controlled inputs, repeatable work, and effective inspection gates. When FPY drops, review the top defect modes, confirm measurement system health, and check for recent material, tooling, or staffing changes that correlate with the decline.
Rolled yield across process steps
Rolled FPY extends the view across multiple stages by multiplying each step FPY. This is critical when early stations look strong but later steps amplify variation. For example, 99% at Assembly, 98% at Inspection, and 97% at Packaging produces about 94.12% rolled yield, revealing a large cumulative loss. Use the step table to identify where yield collapses and focus improvements on the constraint step with the highest defect density.
Defects, opportunities, and DPMO tracking
Defects per million opportunities (DPMO) standardizes defect counts when each unit has multiple defect chances. Enter realistic opportunities per unit based on CTQs, inspection points, or defect categories you audit. A DPMO trend helps compare products with different complexity and supports sigma conversion for executive reporting. If DPMO improves but FPY stays flat, you may be reducing minor defects while major rework drivers remain; prioritize by severity and escape risk.
Cost of poor quality for prioritization
Cost of poor quality converts rework, scrap, and defect handling into money for better decision making. Include labor time, retest cycles, consumables, and lost material value. When COPQ is dominated by scrap, invest in mistake‑proofing and incoming quality. When rework is dominant, standardize work instructions and tighten parameter windows. When defect handling is dominant, improve detection and containment upstream to avoid downstream disruption and customer impact.
Turning results into sustained control
Use the calculator output as a weekly review pack: FPY, rolled FPY, rework rate, scrap rate, and DPMO. Set a target FPY and interpret status consistently across teams. Pair the numbers with actions: corrective owners, due dates, and verification checks. Over time, segment results by machine, supplier lot, or operator certification to find patterns. Combine the results with SPC charts in your quality system for prevention. Keep definitions constant, document scope and sampling, and review measurement bias so month-to-month comparisons stay meaningful.
FAQs
1. What does first pass yield measure?
It measures the share of units that meet requirements the first time, with no rework. FPY is sensitive to stability, methods, and inspection rules, making it ideal for tracking true process performance.
2. Do reworked units count as first-pass good?
No. Reworked units are accepted only after extra effort, so they reduce FPY. Track rework rate separately to quantify labor impact and prioritize fixes that remove the root causes.
3. When should I use rolled FPY?
Use rolled FPY when a unit passes through multiple steps and each step can fail independently. It highlights cumulative loss and pinpoints the stage where yield erosion has the biggest leverage.
4. How do I choose opportunities per unit?
Use the number of defect chances you audit per unit, such as CTQs, inspection checks, or defect categories. Keep the definition consistent over time; otherwise DPMO trends can look better or worse without real change.
5. What if defects seem higher than units?
That can happen when one unit has multiple defects. FPY still uses first-pass good units versus input units. For defect intensity, rely on DPMO and review whether counting rules allow repeats per unit.
6. How can I improve FPY fastest?
Start with the top three defect modes by frequency and cost. Confirm measurement accuracy, standardize work, and tighten critical settings. Add mistake-proofing where human error dominates, and verify improvements with week-over-week FPY and rolled FPY.