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All calculatorsMethodology

DPMO Calculator

Calculate defects per million opportunities, defects per unit and the observed opportunity defect rate without assuming a sigma shift.

Interactive calculator · Method DPMO-1.1 · Last reviewed: 2026-10-05

Calculate your scenario

Total opportunities = inspected units × defined opportunities per unit. DPO = observed defects/total opportunities. DPMO = DPO × 1,000,000. DPU = observed defects/inspected units.

Your inputs

Try an example

Default worked example. Edit the inputs to calculate your scenario.

Default worked example

Defects per million opportunities 3,000 DPMO
Total inspected opportunities 4000
Defects per opportunity 0.003 DPO
Defects per unit 0.012 DPU
Opportunity defect rate 0.3%

12 defects ÷ 4000 defined inspected opportunities × 1,000,000 = 3,000 DPMO. Multiple defects can belong to one unit; defective-unit yield is not determined.

How to use the calculator

Define the counted unit and the number of defect opportunities per unit before entering defects. Use consistent inspection rules across the sample. Read DPO, DPU and DPMO as defect counts, not defective-unit yield.

What the result means

Twelve defects across 1,000 units with four opportunities each yield 3,000 DPMO, 0.003 DPO and 0.012 DPU. The opportunity defect rate is 0.3%; it is not a defective-unit percentage.

Formula and units

Total opportunities = inspected units × defined opportunities per unit. DPO = observed defects/total opportunities. DPMO = DPO × 1,000,000. DPU = observed defects/inspected units. Small nonzero metrics use scientific notation: 1e-9 is 0.000000001.

Worked examples

12 defects across 4,000 opportunities: Inspected units: 1000 units; Defined opportunities per unit: 4 opportunities/unit; Observed defects: 12 defects.
Example result: Defects per million opportunities: 3,000 DPMO; Total inspected opportunities: 4000; Defects per opportunity: 0.003 DPO; Defects per unit: 0.012 DPU; Opportunity defect rate: 0.3%.

One defect across 400 opportunities: Inspected units: 200 units; Defined opportunities per unit: 2 opportunities/unit; Observed defects: 1 defects.
Example result: Defects per million opportunities: 2,500 DPMO; Total inspected opportunities: 400; Defects per opportunity: 0.0025 DPO; Defects per unit: 0.005 DPU; Opportunity defect rate: 0.25%.

Limitations and common mistakes

Use a consistent defect definition and count each opportunity at most once. Multiple defects can occur in one unit. DPMO does not identify how many units are defective, prove unit yield or derive a process sigma level. No automatic 1.5-sigma shift is applied. Incoming inspection describes the inspected sample, not defects removed upstream.

One unit can contain several defects. Do not replace counted defects with defective units or change the opportunity definition just to improve DPMO.

Sources and assumptions

Method DPMO-1.1; last formula review 2026-10-05. Sources and their supported claims. Calculation methodology.

American Society for Quality: DPMO: incoming inspection and process performance limits. ASQ explains the limits of incoming inspection and why it does not establish supplier process sigma.