Engineering tool
PPM, DPMO and defect rate calculator
Convert inspection counts into the quality metrics used in supplier scorecards.
Inputs
Characteristics that could each be defective.
Result
Enable JavaScript to use this calculator. The method and formulas are explained below.
Definitions
Defective ppm = defective units / units × 10⁶
DPU = defects / units
DPMO = defects / (units × opportunities) × 10⁶
FPY ≈ e^(−DPU) (Poisson approximation)
Sigma level ≈ Φ⁻¹(1 − DPMO/10⁶) + 1.5
Notes
Defective ppm counts units with at least one defect; DPMO counts every defect against the number of opportunities. The 1.5σ shift is a convention used in Six Sigma tables, not a physical law.
Use of this toolThis calculator is an educational aid. It is not a substitute for the governing standard, the customer specification or engineering approval. Verify results before using them for acceptance decisions.