Calculator Inputs
Use category counts for detailed analysis. Manual total defects is optional and can override the summed categories.
Example Data Table
| Process | Units | Opp./Unit | Total Defects | Total Opportunities | DPO | DPMO | Yield | Sigma |
|---|---|---|---|---|---|---|---|---|
| Assembly Line A | 1,200 | 6 | 27 | 7,200 | 0.003750 | 3,750.00 | 99.6257% | 4.1738 |
| Packaging Cell B | 850 | 4 | 18 | 3,400 | 0.005294 | 5,294.12 | 99.4720% | 4.0481 |
| Machining Station C | 500 | 9 | 9 | 4,500 | 0.002000 | 2,000.00 | 99.8002% | 4.3784 |
Formula Used
1. Total Opportunities
Total Opportunities = Units Inspected × Opportunities per Unit
2. Defects per Opportunity
DPO = Total Defects ÷ Total Opportunities
3. Defects per Million Opportunities
DPMO = DPO × 1,000,000
4. Estimated Yield
Yield = e-DPO × 100
5. Sigma Level Estimate
Sigma ≈ NORMSINV(1 − DPMO ÷ 1,000,000) + 1.5
6. Severity Score per Unit
(Critical×5 + Major×3 + Minor×1 + Recurring×2 + Hidden×4) ÷ Units
7. Cost of Poor Quality
COPQ = Total Defects × Cost per Defect
How to Use This Calculator
- Enter a process name and the reporting period.
- Add the number of units inspected during that period.
- Enter how many defect opportunities each unit contains.
- Fill in defect counts by category for deeper analysis.
- Use the manual override only when your source provides a verified total defect count.
- Optionally add cost per defect and rework hours for operational impact estimates.
- Press Calculate DPO to display results above the form.
- Review the graph, compare categories, then export the report as CSV or PDF.
Frequently Asked Questions
1. What does defects per opportunity measure?
It measures how often defects occur relative to the total number of possible defect opportunities. This makes comparisons fairer across products, batches, or processes with different complexity levels.
2. Why is DPO better than counting defects alone?
Raw defect totals ignore how many chances a defect had to occur. DPO normalizes defects against opportunity volume, so one process is not unfairly judged against another.
3. What is the difference between DPO and DPMO?
DPO is the base ratio of defects to opportunities. DPMO simply scales that ratio to one million opportunities, making Six Sigma benchmarking easier and easier to communicate.
4. Can this calculator estimate sigma level?
Yes. It estimates sigma from DPMO using a common long-term conversion with a 1.5 sigma shift. This is useful for process comparisons, but it remains an approximation.
5. Should I use manual total defects override?
Use it when audited totals are available from another system and category detail is incomplete. The override should never be smaller than the sum of categorized defects.
6. What does estimated yield mean here?
Estimated yield is the probability of producing an opportunity set without defects, based on the entered DPO. It gives a quick view of expected process performance.
7. Why include defect cost and rework hours?
Those inputs translate quality problems into business impact. Teams can see how a small defect rate can still create meaningful cost, delay, and capacity loss.
8. Can I use this for services or transactions?
Yes. A unit can be a document, transaction, customer case, or service ticket. Opportunities are the measurable checkpoints where a defect could occur.