AQL in Garment Inspection: The 2.5 Standard Explained

AQL is the maximum share of defects a buyer accepts in a lot before rejecting it. Apparel almost always uses 0 critical, 2.5 major, 4.0 minor. You inspect a sample, not the whole order: the lot size and inspection level set the sample size and the accept or reject numbers via ISO 2859-1 tables.

In Soo Seguier September 1, 2026 7 min

No brand inspects 5,000 finished garments one by one. AQL is the rule that lets a factory and a buyer agree, before production, on how much is wrong is too wrong: inspect a random sample, count the defects, and pass or fail the whole shipment against an agreed threshold.

It is the backbone of pre-shipment quality control, and this guide covers what AQL means, the defect classes, the apparel standard, and how the sampling actually works, as part of sourcing production well.

What is AQL (Acceptable Quality Limit)?

AQL, the Acceptable Quality Limit, is the worst level of quality a buyer is willing to tolerate in a batch. Put simply, it is the maximum percentage of defective items allowed in a lot before that lot is rejected. An AQL of 2.5 means up to 2.5% of the units can be defective and still pass.

The standard behind it, ISO 2859-1 (also published as ANSI/ASQ Z1.4), defines the AQL as the quality level that is the worst tolerable. It accepts a realistic truth: mass production is never perfect, so the useful question is not whether there are defects but whether there are too many. It was once called the Acceptable Quality Level, and the two names are used interchangeably.

The three defect classes: critical, major, minor

AQL is not a single number. It is set separately for three classes of defect, because a safety hazard and a loose thread are not the same problem.

Critical: a defect that makes the product unsafe or breaks a regulation, such as a broken needle left in a garment. The AQL is 0, so a single critical defect fails the whole lot.
Major: a defect a customer would notice and likely return the product for, such as a broken seam, the wrong size, or a clear stain. The apparel AQL is usually 2.5.
Minor: a small cosmetic flaw that does not affect use or saleability, such as a slightly loose thread or a faint mark. The apparel AQL is usually 4.0.

Which specific faults fall into each class is the buyer's call, not the inspector's. When a buyer does not define them, inspectors apply the industry default of 0 / 2.5 / 4.0, but the safest practice is to spell out your own defect list, ideally with photos.

In garments the same faults recur, and naming them by class is what makes an inspection repeatable. Broken or skipped stitches and open seams, measurements outside tolerance, shade variation between panels, crooked logos or prints, stains and oil marks, and mislabeled size or care content are the usual ones. Most are majors; a faint mark or a slightly uneven hem is often a minor; a broken needle or a banned chemical is critical.

What does AQL 2.5 mean in apparel?

AQL 2.5 means up to 2.5% of major defects in the sampled units is acceptable. It is the near-universal apparel standard for major defects, written in full as General Level II, AQL 0 / 2.5 / 4.0 for critical, major and minor.

You can move it. A premium or higher-risk product might tighten majors to 1.5 or 1.0; a low-cost basic where cosmetics matter less might loosen minors. The trade-off is fixed: a lower AQL is a stricter quality bar, which catches more bad product but also rejects more lots, so it costs more in reworks and delays. The right level matches the product's price and risk, not the highest number you can name.

How AQL sampling works: from lot size to accept or reject

You inspect a random sample, not the whole order, and three inputs turn that sample into a pass or fail.

Lot size and inspection level (General Level II by default) map to a sample-size code letter.
The code letter maps to a sample size, the number of pieces to pull and inspect.
The sample size and your chosen AQL give an acceptance number (Ac) and a rejection number (Re) for each defect class.

A worked example makes it concrete. An order of 5,000 units inspected at General Level II maps to code letter L and a 200-piece sample. At the standard apparel AQL, the shipment passes with no critical defects, 10 or fewer major (Ac 10, Re 11), and 14 or fewer minor (Ac 14, Re 15). Find 11 major defects in those 200 pieces and the whole 5,000-unit lot is rejected, even though you only looked at 200.

AQL inspection levels

The inspection level decides how big the sample is relative to the lot. Most apparel uses the General levels; special levels exist for tests that are slow or destructive.

General Level I: a smaller sample and a lighter, cheaper check, used for trusted suppliers or lower-risk goods.
General Level II: the default for apparel, a balanced sample size that most brands and inspectors assume unless told otherwise.
General Level III: a larger sample for tighter scrutiny, used for new suppliers or high-risk product where a bigger check is worth the added cost.

There are also four special levels (S1 to S4) with much smaller samples, reserved for checks that are expensive or destroy the unit, such as a lab test on a fabric sample rather than a visual pass over the lot.

When AQL inspection happens

The classic AQL checkpoint is the pre-shipment inspection, also called the final random inspection, run once at least 80% of the order is produced and packed. It is the last gate before goods leave the factory, and it sits inside the wider fashion supply chain of checks that also includes inline and during-production inspections.

Timing matters because AQL only tells you the state of what already exists. A pre-shipment fail this late means rework or a delayed shipment, which is why brands that inspect only at the end tend to firefight, while those who also check during production catch the same defects while they are still cheap to fix.

How to set AQL with your factory

AQL works only when both sides agree the numbers before production, not after a dispute. Treat it as part of the quality agreement, alongside the specification the factory is building to.

Write it into the tech pack: your quality tolerances and defect definitions belong in the tech pack, so the factory builds to the same standard the inspector later checks against.
Agree the AQL before the PO: fix the levels for critical, major and minor, and the inspection level, in writing before the order is placed, not when a shipment is already in dispute.
Vet the factory first: an AQL is a safety net, not a substitute for choosing a capable maker; it pairs with finding the right manufacturer in the first place.
Use an independent inspector: a third party with no incentive to pass the lot gives a truer reading than the factory's own sign-off, and applies your AQL consistently across every supplier.

From a pass or fail to a sourcing decision

One AQL result grades one shipment. The sharper signal is the pattern: which suppliers pass first-time, which classes of defect keep recurring, and where quality is quietly drifting across seasons. Apshan builds that connected, sourced read on production and supply. See how it informs textile sourcing, request access, or view the plans and pricing.

Questions

What does AQL stand for?

AQL stands for Acceptable Quality Limit, sometimes written Acceptance Quality Limit or, historically, Acceptable Quality Level. It is the maximum percentage of defective units a buyer will tolerate in a production lot before the lot is rejected, defined by the ISO 2859-1 sampling standard.

What is AQL 2.5?

AQL 2.5 means up to 2.5% of the sampled units can carry a major defect and the lot still passes. It is the standard setting for major defects in apparel, applied alongside 0 for critical defects and 4.0 for minor ones at General Inspection Level II.

What is the AQL for garments?

The apparel standard is General Level II with an AQL of 0 for critical defects, 2.5 for major and 4.0 for minor. Higher-risk or premium products may tighten the major level to 1.5 or 1.0, while lower-cost basics may loosen the minor level.

What are critical, major, and minor defects?

Critical defects make a product unsafe or non-compliant and carry an AQL of 0, so one fails the lot. Major defects are faults a customer would notice and return, at AQL 2.5. Minor defects are small cosmetic flaws that do not affect use, at AQL 4.0. The buyer defines which faults fall where.

How is AQL sample size calculated?

Sample size comes from two inputs: the lot size and the inspection level. You find the lot-size row in the ISO 2859-1 table, read across to your level (General II by default) for a code letter, and the code letter gives the sample size and the accept or reject numbers. A 1,000-unit lot at Level II gives a sample of about 80.

Is a lower AQL better?

Not automatically. A lower AQL is a stricter quality bar that catches more defects, but it also rejects more lots and raises rework and cost. The right AQL matches the product's price point and risk, so a safety-critical item is tighter than a low-cost basic.