DHU and defective percentage calculator
Two inline-quality rates that are often confused: defects per hundred units and the percentage of pieces that are defective. Both use pieces inspected as the denominator; they differ in what they count.
How this is calculated
DHU = total defects ÷ pieces inspected × 100. Defective % = defective pieces ÷ pieces inspected × 100, where a defective piece is one with at least one defect, counted once. First-pass yield = 100 − defective %.
Worked example. 500 pieces inspected; 60 defects found on 45 pieces. DHU = 60 ÷ 500 × 100 = 12.00. Defective = 45 ÷ 500 × 100 = 9.00%, first-pass yield 91.00%, and 1.33 defects per defective piece.
Questions
- Which should I report, DHU or defective %?
- Both answer different questions. DHU counts defects and shows how much repair work the line is generating; defective % counts pieces and shows how many garments failed. A line fixing its worst operation may cut DHU sharply while defective % moves less.
- Can DHU be more than 100?
- Yes. 120 DHU means 120 defects per 100 pieces - several defects on some garments. Defective % cannot exceed 100.
- Is DHU the same as AQL?
- No. AQL is a sampling plan for accepting or rejecting a lot; DHU is a rate measured on whatever you inspected. Use the AQL calculator for lot acceptance.
Sources & verification
DHU and percent defective are the standard attribute measures of inline and end-line inspection in apparel quality control; the definitions above are stated explicitly so they can be matched to your own QC manual. The worked example is recomputed in the automated tests.