Guide · Quality
AQL quality inspection, explained
You can't check every piece in a 20,000-unit order, so buyers inspect a statistically chosen sample. AQL is the agreed rule for how many defects are acceptable. Here's how it works in plain terms.
What AQL means
AQL (Acceptable Quality Limit) is the maximum percentage of defective units that will still allow a batch to pass, defined by the international acceptance-sampling standards ISO 2859-1 (and the equivalent ANSI/ASQ Z1.4). An inspector checks a random sample from the lot, counts defects, and compares them against an acceptance number — pass if at or below it, fail if above.
Defects are graded
| Class | What it is | Common AQL |
|---|---|---|
| Critical | Safety or legal risk to the wearer | 0 (none accepted) |
| Major | Affects saleability or function (would likely cause a return) | 2.5 |
| Minor | Small cosmetic flaw unlikely to affect a sale | 4.0 |
The AQL 2.5 / 4.0 pairing is a common default in apparel, but the exact levels are agreed between buyer and supplier for each programme.
How sample size is set
Sample size depends on the lot size and the inspection level (General Inspection Level II is the usual default). The standard's tables give a code letter for your lot size, and the code letter plus the AQL gives the sample size and the accept/reject numbers.
When to inspect
- In-line / during production (DUPRO) — catch issues while there's still time to correct them.
- Final random inspection (FRI) — on finished, packed goods (often once ~80% is produced and packed).
- Lab tests — for knitwear, plan dimensional stability (shrinkage), colourfastness and similar where relevant.
What to agree before production
- AQL for major and minor defects
- Inspection level and who inspects
- A defect classification list (what counts as major vs minor)
- Whether you get photo reports, and how a failed inspection is handled (re-work, re-inspect)
Related
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