PPM

parts per million defective

PPM = (P(x < LSL) + P(x > USL)) · 10⁶

Defective parts per million. Observed PPM counts the values outside the limits in the sample. Expected PPM is calculated from the fitted distribution and estimates the long-run defect rate, including defects too rare to appear in the sample.

Calculate it

Cpk, PPM and Sigma Converter: Convert Cpk, PPM, yield and sigma level, with or without 1.5 σ shift.

Related terms

• Cpk: process capability index
• Sigma level: Six Sigma performance scale