AQL Inspection Explained

What AQL means

Acceptable Quality Limit. It defines the maximum defect rate a buyer is willing to accept in a shipment, and it drives a sampling plan: how many garments to pull from the order, and how many defects in that sample trigger a rejection.

Inspectors do not check every unit. They check a defined random sample and infer the state of the whole batch from it.

The thing almost everyone gets wrong

AQL 2.5 does not mean “2.5% of my order is allowed to be faulty”. It means the sampling plan is calibrated so that batches whose true defect rate exceeds 2.5% are rejected with a defined statistical confidence. It is a decision rule about the batch, not an allowance you have granted.

The three defect classes

• Critical — zero tolerance. Unsafe, non-compliant, or unsellable in any condition: wrong fabric or colour, open seams or holes, missing care/content labelling, a safety failure.
• Major — commonly AQL 2.5. Affects appearance, fit or function enough to cause a return: measurements beyond tolerance, visible shading between panels, broken or skipped stitching, misplaced print, non-functional trims.
• Minor — commonly AQL 4.0. Cosmetic and within commercial tolerance: loose threads, slight puckering inside tolerance, minor pressing marks, small label placement variance.

Critical 0 / major 2.5 / minor 4.0 is the conventional apparel setting. It is a convention, not a law — agree yours in writing before production, because after the fact it is unarguable.

How the sample size is chosen

From the lot size and an inspection level — general level II is the usual default. The lot size and level give a sample size code, and the code plus the AQL gives the sample size and the accept/reject numbers. Your inspector works from the standard tables; you do not need to memorise them, but you should know which level was used.

A higher inspection level means a bigger sample and more confidence, at more cost. Worth paying for on a first run with a new factory.

What a rejection actually means

It does not mean the goods are unsellable. It means the batch failed the agreed decision rule, and the next step — sort, rework, re-inspect, discount, or reject outright — is whatever the production agreement says it is. Which is exactly why that has to be in the agreement.

Making it work for you

1. Agree the AQL levels and inspection level in writing before production starts
2. Make sure a sealed PP sample and a graded spec with tolerances exist, or there is nothing to inspect against
3. Insist the sample is drawn randomly across cartons, sizes and colourways — not hand-picked
4. Require measurements across the whole size range, not just the base size
5. Tie the balance payment to a passed inspection
6. Agree in advance who pays for rework and re-inspection

The limit of AQL

It catches what the sample reveals. It will not catch a problem that develops later — shrinkage on first wash being the classic. For that you need testing before bulk, not inspection after it.