Enter process data
Use defects, direct DPMO, or yield percentage. The input grid uses three columns on large screens, two on smaller screens, and one on mobile.
Example data table
| Process | Units | Opp./Unit | Defects | DPO | DPMO | Yield | Short-Term Sigma |
|---|---|---|---|---|---|---|---|
| Assembly Line A | 12,000 | 5 | 38 | 0.000633 | 633 | 99.9367% | 4.72 |
| Packaging Cell B | 8,500 | 4 | 52 | 0.001529 | 1,529 | 99.8471% | 4.47 |
| Machining Line C | 4,300 | 7 | 96 | 0.003189 | 3,189 | 99.6811% | 4.22 |
These rows are sample values for learning and benchmarking. Your live results are calculated from the form above.
Formula used
- Total Opportunities = Units Inspected × Opportunities per Unit
- DPU = Total Defects ÷ Units Inspected
- DPO = Total Defects ÷ Total Opportunities
- DPMO = DPO × 1,000,000
- Yield = (1 − DPO) × 100
- First Pass Yield = ((Units − Defective Units) ÷ Units) × 100
- Rolled Throughput Yield = e−DPU × 100
- Long-Term Sigma = NORMSINV(Yield Probability)
- Short-Term Sigma = Long-Term Sigma + Sigma Shift
This calculator uses an inverse normal approximation to translate yield probability into sigma level. A 1.5 sigma shift is commonly applied for short-term reporting.
How to use this calculator
- Choose your preferred calculation mode: defects, DPMO, or yield.
- Enter the quality data available from your inspection or reporting system.
- Adjust the sigma shift if your organization uses a different convention.
- Press the calculate button to generate sigma, yield, and defect metrics.
- Review the summary cards and detailed table above the form.
- Download the result as CSV or PDF for audits, meetings, or improvement reviews.
FAQs
1. What does process sigma measure?
Process sigma estimates how well a process avoids defects. Higher sigma levels mean fewer defects, better yield, and more stable performance over time.
2. Why does the calculator include DPMO?
DPMO standardizes defects across different processes by using one million opportunities. This makes comparisons easier between lines, products, teams, or plants.
3. What is the difference between DPU and DPO?
DPU uses defects per unit, while DPO uses defects per opportunity. DPO is more detailed because it considers multiple defect opportunities within each unit.
4. Why is a 1.5 sigma shift used?
Many quality teams use a 1.5 sigma shift to reflect long-term process drift. It converts long-term capability into a more familiar short-term sigma figure.
5. Can I calculate sigma from yield only?
Yes. Choose the yield mode, enter the percentage yield, and the calculator will estimate DPMO, long-term sigma, and short-term sigma automatically.
6. What is first pass yield?
First pass yield shows the percentage of units that passed without rework or repair. It is useful when you know how many units were defective.
7. What is rolled throughput yield?
Rolled throughput yield estimates the probability that a unit moves through the process without defects. It is especially helpful for multi-step workflows.
8. When should I use this calculator?
Use it during audits, monthly reviews, process improvement projects, supplier evaluations, or any quality meeting where defect performance and capability need clear measurement.