Skip to main content

PPM (Parts Per Million)

A defect rate metric expressing how many units out of one million are non-conforming.

Definition and context

PPM expresses a count per million units. State whether the count is nonconforming units or individual nonconformities; these measure different things.

Calculate nonconforming-unit PPM

If 12 of 40,000 inspected units are nonconforming, PPM = 12 / 40,000 × 1,000,000 = 300. Count each nonconforming unit once, even if it has several defects. This is an illustrative calculation.

Keep the denominator consistent

Compare periods only when inspection coverage, product scope and counting rules match. Sample results describe the inspected sample; do not present them as a full-lot count. Investigate changes in product mix or inspection before attributing a decrease to corrective action.

Where this term fits in the workflow

PPM (Parts Per Million) is usually shown in the performance and improvement.

Terms tied to continuous improvement, supplier performance, line discipline, and long-term quality reporting.

What is KaizenQ?

KaizenQ helps factory teams record inspection results, defect photos, and notes in one report shared with the office.

Learn more
KaizenQ inspection report preview

Key takeaways

  • Record the numerator, denominator and inspection scope with every PPM result.

Compare with related terms

Next terms to read