AQL stands for acceptance quality limit. At a final random inspection nobody checks every piece of a large order, so a sample is drawn at random and the whole lot is accepted or rejected on the number of defects found in it. ISO 2859-1 sets how many pieces to draw for a lot of a given size and how many defects each AQL allows in that sample. The figure is a sampling rule, not a promise of a fault free order: at AQL 2.5, some defective pieces can still reach your warehouse.
On orders placed through Garments Hub BD, inline inspection runs during sewing, and the final random inspection is held at 80 percent packed, to AQL 2.5 unless you specify otherwise. Every stage is photographed and the photographs are yours. You may also book a third party inspector of your choice, whose report overrules the desk's own.
From lot size to sample size in ISO 2859-1
Reading the tables takes three steps. First, the lot size: the number of pieces of the style presented for inspection. Second, the inspection level: general inspection level II is the usual choice for garments, while levels I and III draw fewer or more pieces. Third, the code letter that the lot size and level give, which leads to the sample size. The figures below are for general inspection level II, single sampling, normal inspection, with the acceptance numbers at AQL 2.5 and 4.0. Notice that the sample grows far more slowly than the lot.
- 281 to 500 pieces: code letter H, sample 50. AQL 2.5 accepts 3 and rejects at 4; AQL 4.0 accepts 5 and rejects at 6.
- 501 to 1,200 pieces: code letter J, sample 80. AQL 2.5 accepts 5, rejects at 6; AQL 4.0 accepts 7, rejects at 8.
- 1,201 to 3,200 pieces: code letter K, sample 125. AQL 2.5 accepts 7, rejects at 8; AQL 4.0 accepts 10, rejects at 11.
- 3,201 to 10,000 pieces: code letter L, sample 200. AQL 2.5 accepts 10, rejects at 11; AQL 4.0 accepts 14, rejects at 15.
- 10,001 to 35,000 pieces: code letter M, sample 315. AQL 2.5 accepts 14, rejects at 15; AQL 4.0 accepts 21, rejects at 22.
What AQL 2.5 major and 4.0 minor allow on an order
A worked example. An order of 3,000 T-shirts falls in the 1,201 to 3,200 band, so the inspector draws 125 pieces at random from cartons across the lot. Major and minor defects are counted separately on the same 125 pieces. With 7 or fewer major defects the lot passes on majors; at 8 it fails. With 10 or fewer minor defects it passes on minors; at 11 it fails. A fail on either count fails the lot.
AQL 2.5 does not mean that 2.5 percent of the sample may be defective; 7 of 125 is already 5.6 percent. It means the plan is built to accept, most of the time, lots whose true defect rate is 2.5 percent or lower. A lot with more defects than that can still pass by chance, which is why inline inspection, catching faults while the line can change, matters as much as the final count.
When AQL 1.5 is worth the stricter limit
AQL 1.5 is strict. At most lot sizes the sample stays the same and the acceptance number falls: on 125 pieces, 5 major defects are accepted at AQL 1.5 against 7 at AQL 2.5. On small lots the table's arrows can move a strict AQL to a larger sample. A worked example: a lot of 100 pieces is inspected on 20 pieces at AQL 2.5, accepting 1 major, but at AQL 1.5 the arrow leads to 32 pieces, still accepting 1.
AQL 1.5 suits garments where a fault is costly after delivery: high value pieces, children's wear, uniforms bought against a contract, or a first order with a new factory. Expect more lots to need sorting, and some factories to price the stricter limit in.
Critical, major and minor defects in garments
Each defect found is placed in one class, and the class decides which limit it counts against. Write your own defect list for the garment, because the class of a defect depends on the product: a loose button is a nuisance on a coat and a hazard on babywear. Critical defects are usually set at zero accepted, so one critical defect fails the lot.
- Critical: a risk to the wearer or a breach of a legal rule, such as a broken needle in the garment, sharp metal, or a cord on children's wear outside the rules.
- Major: likely to cause a return or stop a sale, such as an open seam, a hole, a stain seen at arm's length, a shade difference between panels, a wrong size label or a measurement out of tolerance.
- Minor: noticed on close inspection but unlikely to stop a sale, such as an untrimmed thread end, a slightly uneven stitch line or a small mark that brushes off.
Measurement tolerances
Measurements are taken on an agreed, smaller number of pieces per size and compared with the size chart. A tolerance is needed for each point of measure; without one, an inspector has no basis to fail a piece. Commonly the tolerance is 1 cm either way on large points such as chest, body length and waist, and less on small points such as neck width or cuff opening. Agree whether a reading outside tolerance counts as a major defect, which is the usual practice.
What a failed inspection triggers
A fail rejects the lot, not only the pieces found. The usual course is that the factory sorts the whole lot, repairs or replaces the defective pieces, and the lot is inspected again on a fresh sample at the same AQL. That takes days and can move the ship date. You may instead accept a failed lot on agreed terms, but that is your decision, made in writing. Set out the procedure and who bears the cost of a re-inspection before the order is confirmed, not after a fail.
Writing the AQL into the proforma invoice
The inspection terms belong in the proforma invoice or the purchase contract, where both sides sign them. State the standard and plan (ISO 2859-1, general inspection level II, single sampling, normal inspection), the AQL for each class, the timing of the final random inspection, the measurement tolerances, the approved references, and the procedure after a fail. If you plan to use a third party inspector of your choice, name that in the same place, so the factory expects the visit.
What to put in your inspection terms
- Standard and planISO 2859-1, general inspection level II, single sampling, normal inspection, written in the proforma invoice.
- AQL by classZero for critical defects, 2.5 for major and 4.0 for minor, or 1.5 for major if you need it stricter.
- Defect listWhat counts as critical, major and minor on this garment, with examples agreed before production.
- Measurement tolerancesA tolerance for each point of measure and the number of pieces measured in each size.
- TimingInline inspection during sewing and the final random inspection at 80 percent packed.
- ReferencesThe signed PP sample, approved lab dips and trim card that the inspector compares against.
- After a failSorting, repair, re-inspection at the same AQL, and who bears the cost of the second visit.
Questions buyers ask
Does AQL 2.5 mean 2.5 percent of my order can be defective?
Not exactly. AQL 2.5 sets how many defects are accepted in the sample, and the plan is built to accept most lots whose true defect rate is 2.5 percent or lower. On a sample of 125, up to 7 major defects pass. Some lots with a higher defect rate will still pass by chance.
Why does the inspection wait until 80 percent is packed?
Because the sample must represent the lot. Once most of the order is finished and packed, the inspector can open cartons from different positions and draw pieces across sizes and colours. An inspection held earlier sees only what has been made so far, and faults in the remaining work can go unseen.
Should each colour be inspected as a separate lot?
Usually the lot is the quantity of a style presented for inspection, with the sample spread across colours and sizes in proportion. Some buyers treat each colour as its own lot, which means more pieces inspected in total. Decide which you want and write it into the inspection terms before the order is confirmed.
Who pays for a re-inspection after a failed lot?
Whoever the contract says. Agree it in writing before the order is confirmed. Many buyers write that the cost of a re-inspection after a fail falls on the factory, since the fail arose in production. A third party inspector of your choice bills each visit, so an unplanned second visit is a real cost.
What AQL should I set on a first order?
AQL 2.5 for major defects and 4.0 for minor is a common apparel setting, with critical defects at zero. Choose 1.5 for major defects on high value or children's goods. The AQL is only one part of control: inline inspection during sewing and clear measurement tolerances prevent more problems than a stricter final limit.
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