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Six Sigma DPMO Calculator

Convert defects, units and opportunities into DPMO, DPU, yield and sigma level (with the standard 1.5σ shift).

Defects found

Units inspected

Opportunities per unit

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How it works

DPMO = defects ÷ (units × opportunities) × 1,000,000 · σ = Φ⁻¹(1 − DPMO/10⁶) + 1.5

DPMO normalises defect counts by how many things could have gone wrong, so products of different complexity can be compared. The sigma level is the normal quantile of the yield, plus the conventional 1.5σ long-term drift allowance — which is why Six Sigma corresponds to 3.4 DPMO rather than 0.002.

Worked example

34 defects in 1,500 units with 5 opportunities each: 34 ÷ 7,500 × 10⁶ = 4,533 DPMO → about 4.1σ.

Frequently asked questions

Why add 1.5 sigma?

Motorola’s convention: processes drift over time, so short-term capability is assumed 1.5σ better than long-term performance.

What counts as an opportunity?

Each independent way a unit could fail a requirement. Keep the definition consistent or DPMO becomes meaningless.

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