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Supplier Defective Parts per Million Calculator
Calculate defective units per million from one assessed supplier cohort, keeping unit failures separate from multiple defect events.
Supplier defective-unit PPM calculator
Calculate defective units per million from one assessed supplier cohort, keeping unit failures separate from multiple defect events.
YOUR RESULT LIVE CALCULATION
Observed defective-unit PPM
2,500defective units / million
ONE FAILED UNIT COUNTS ONCE- Observed defective-unit rate
- 0.25%
- Units meeting assessed criteria
- 99,750
- Observed conforming-unit rate
- 99.75%
- Assessed / defective units
- 100,000 / 250
This is the observed assessed cohort, not DPMO or a confidence bound for uninspected units.
BEHIND THE NUMBER
How the calculation works
Count each failed unit once even if it has several defects. The numerator and denominator must describe the same inspected or otherwise assessed cohort and the same defect criteria. PPM scales the observed rate to one million units; it does not mean one million units were inspected.
Defective-unit PPM = defective units / assessed units x 1,000,000
When this calculation helps
Defective-unit PPM counts units with at least one qualifying defect per million assessed units. This can make small rates easier to compare while preserving the inspected-unit denominator.
Check the interpretation
It is not a count of every defect occurrence, and a sampled population may not represent all delivered units. Keep inspection coverage and defect definitions stable. A zero count in a small sample is not proof that the process produces no defects.
This is not defects per million opportunities, a statistical confidence interval, or a lot-acceptance plan. Sampling results do not establish the exact defect rate in uninspected receipts. Zero observed failures does not prove zero underlying risk.
ASQ quality glossary: PPM and defect measuresGood to know
Can one unit contribute more than one failure?
Not here. This is defective-unit PPM. A unit with three defects counts as one defective unit. Defect-event and opportunity-based measures have different numerators and denominators.
What if no failures are observed?
The observed PPM is zero for this cohort. Do not interpret that as proof that every uninspected unit is defect-free.