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AQL inspection China · buyer decision guide

AQL Inspection in China: Sample Size and Defect Limits

Written by Agent HuangPublished on June 19, 2026

China-side sourcing partner helping overseas buyers verify suppliers, inspect goods, and reduce payment or shipment risk before money or goods move.

An AQL inspection in China uses a defined random sample to make an accept-or-reject decision about a production lot. Before the factory visit, the buyer should approve the sampling standard, lot size, inspection level, defect definitions, AQL values, and action to take when a limit is reached.

AQL does not mean that the accepted lot contains only that percentage of defects. It is an index used with a sampling plan. The plan converts the lot size and inspection level into a sample size, then sets acceptance (Ac) and rejection (Re) numbers for each defect class.

Plan My AQL Inspection See Worked Example

Inspector measuring sampled products beside packed cartons during an AQL inspection in China

DefineLot DefineLevel DefineSample DefineAc / Re

Quick answer

What must be fixed before an AQL inspection starts?

Freeze the sampling plan and the product-specific defect rules before anyone counts a defect. Otherwise the factory, inspector, and buyer can use different assumptions and produce a number that does not support a defensible shipment decision.

1Name the sampling standard and edition in the purchase order or inspection instruction

2Define the lot by product, model, color, size, production batch, and packed quantity

3Choose the inspection level before using the lot-size table to find a code letter

4Use the code letter and plan type to determine the random sample size

5Approve critical, major, and minor defect definitions with product-specific examples

6Assign an AQL or zero-tolerance rule to each defect class before inspection

7Record both defective units and individual defects consistently in the report

8Decide in advance whether rejection triggers sorting, rework, re-inspection, or a payment hold

Sampling workflow

How an AQL sample becomes a lot decision.

AQL is not one percentage applied to every order. It is a sequence of decisions that must remain traceable from the contract to the inspection report.

Define the lot

Confirm the units available for inspection and keep different SKUs or production batches traceable. A vague or incomplete lot makes the sample decision unreliable.

Choose the plan

State the standard, normal/tightened/reduced status, single/double/multiple plan, and inspection level. General Level II is common, but it is not automatically correct for every product or risk.

Find the sample size

Use the lot-size and inspection-level table to find the code letter, then use the applicable sampling-plan table to find the number of randomly selected units.

Apply Ac/Re limits

Count results by the buyer-approved defect classes. Accept when the count is at or below Ac; reject when it reaches Re. Do not invent a percentage after the inspection.

Worked example

Sample size and defect limits for a 1,200-unit lot.

This common configuration shows how the plan is read. It is not a universal recommendation for every product, buyer, or isolated shipment.

Plan inputs

Lot: 1,200 finished units of one SKU
Plan: Normal inspection, single sampling
Level: General Inspection Level II
Code / sample: Code letter J / 80 randomly selected units

Defect class

Illustrative rule

Decision

Critical

Buyer sets zero tolerance

1 critical defect triggers a hold and investigation

Major

AQL 2.5: Ac 5 / Re 6

0–5 accept; 6 or more reject

Minor

AQL 4.0: Ac 7 / Re 8

0–7 accept; 8 or more reject

Illustrative configuration only: confirm the current licensed standard and the buyer-approved inspection instruction before using these numbers.

Classification

Critical, major, and minor must be product-specific.

Critical defect

A condition that could create an unsafe or unlawful product, or another buyer-defined severe risk. Examples may include an exposed live conductor, a sharp point on a children’s item, or the wrong safety-critical component. Critical criteria require product and market context; do not copy a generic list blindly.

Major defect

A defect likely to cause product failure, materially reduce normal usability, or make the product unsaleable to the intended customer. Examples may include a non-working function, wrong model, missing essential accessory, open seam, or materially incorrect dimension.

Minor defect

A departure from the approved requirement that does not materially prevent normal use but still affects finish, consistency, or presentation. Examples may include a small cosmetic mark outside a controlled appearance area or slight print-position variation within an agreed tolerance.

Buyer decision table

What to do with the AQL result.

Inspection signal

What it means

Buyer action

Counts are at or below every Ac number

The sampled lot meets the stated acceptance plan for the inspected points.

Review all report findings, tests, quantity, packing, and open issues before release; AQL is only one decision input.

Any count reaches its Re number

The sampled lot fails the agreed plan for that defect class.

Hold release, identify the affected pattern, require controlled sorting or rework, and define re-inspection.

A critical issue appears

A severe risk exists even if other AQL counts are low.

Stop the release decision and investigate scope, cause, affected stock, and any testing or compliance escalation needed.

Sample access or randomness is compromised

Factory-selected samples, blocked cartons, or incomplete goods weaken the result.

Record the limitation, restore access or reschedule, and do not present the result as a valid full-lot decision.

The defect list was not approved

Inspector and buyer may classify the same issue differently after the fact.

Pause the decision, document the issue, and establish product-specific classifications before relying on the counts.

Evidence basis for this advice.

This AQL guidance is based on the standards, buyer-approved files, physical lot access, and release-stage facts needed to turn a sample into a documented decision.

Buyer-approved purchase order, product specification, golden sample notes, tolerances, packaging files, label files, and function-test requirements.
A named acceptance-sampling standard and edition, lot definition, inspection level, plan type, sample size, defect classes, and Ac/Re limits.
Randomly selected physical units connected to the packed production lot, with photos, measurements, test results, defect counts, and carton traceability.
Buyer-stage context including balance payment, correction access, pickup timing, shipment deadline, and the agreed response to a rejected lot.

What to send before booking.

The inspector needs the decision rules before arriving at the factory, not after defects appear.

Purchase order, final product specification, approved sample notes, and SKU breakdown
Total finished lot quantity and packed quantity by SKU, color, size, or batch
Named sampling standard, edition, inspection level, and plan status if contractually specified
Critical, major, and minor defect list with product-specific photos or examples
AQL values or other acceptance rules approved for each defect class
Required function tests, measurement tolerances, packaging checks, and label checks
Balance-payment deadline, pickup date, and required action after a rejection

Scope limits

What passing AQL cannot prove.

Sampling controls inspection effort and formalizes a lot decision. It does not remove sampling risk or expand a visual check into certification.

An accepted sample does not prove that every unit in the lot is conforming or defect-free
AQL is an acceptance-sampling index, not a promise that the shipment contains exactly the stated percentage of defects
A visual AQL inspection does not replace product certification, laboratory testing, engineering validation, or legal compliance review
A sampling result is only as reliable as the lot definition, random access, approved checklist, defect classification, and execution evidence
Special, destructive, time-consuming, or safety-critical tests may need separate sample sizes or test plans
ISO 2859-1 is designed around continuing series of lots and switching rules; buyers applying a plan to an isolated lot should evaluate whether the selected plan gives the protection they need

Standards sources

Verify the standard behind the plan.

ISO 2859-1:2026 is the current ISO edition. Use the licensed standard or the sampling standard named in your contract for operative tables and rules.

ISO 2859-1:2026

Current ISO standard for AQL-indexed lot-by-lot inspection by attributes; Edition 3 was published in January 2026.

ASQ: ANSI/ASQ Z1.4 and Z1.9

Overview of the U.S. acceptance-sampling standards, including normal, tightened, and reduced plans.

ASQ: attribute and variable sampling

Definitions and context for attribute sampling, acceptance criteria, and sampling-plan use.

Related next steps

Move from the plan to buyer-side evidence.

QC Inspection China

Plan product, quantity, function, packaging, and AQL evidence before balance payment.

Open page

China QC Booking Checklist

Prepare the files and decision rules the inspector needs before the factory visit.

Open page

QC Before Balance Payment

Connect the inspection result to the approve, hold, correct, or re-inspect decision.

Open page

Sample Inspection Report

See how buyer-side photos, findings, limits, and release notes can be structured.

Open page

Frequently asked questions

What does AQL mean in a China inspection?

AQL means acceptance quality limit. It is an index used with an acceptance-sampling plan to select sample size and acceptance or rejection numbers for a lot. It is not a guarantee that the lot contains a specific defect percentage.

How is the AQL inspection sample size chosen?

The selected standard combines lot size and inspection level to produce a code letter. The applicable sampling-plan table then converts that code letter into a sample size. The plan type and normal, tightened, or reduced status also matter.

What AQL should I use for critical, major, and minor defects?

There is no universal setting for every product. Many buyers use stricter rules for critical and major defects than for minor defects, but the values and definitions should follow product risk, customer requirements, contract terms, and applicable standards. Safety-critical issues may need zero tolerance or separate testing.

Does passing AQL mean the whole shipment is defect-free?

No. Passing means the random sample met the stated acceptance plan for the inspected requirements. Uninspected units can still contain defects, and hidden, future, laboratory, or compliance issues may remain outside scope.

What should I do when an AQL inspection fails?

Hold payment or shipment release where contractually possible, review the defect pattern, require controlled sorting or rework, document affected stock, and schedule a new random re-inspection under an agreed plan. Do not rely only on selected correction photos.

What changed in ISO 2859-1:2026?

ISO states that Edition 3 replaced the 1999 edition and its amendments, added skip-lot sampling procedures, and updated guidance for applying sampling strategies. Buyers should name the intended edition in contracts and inspection instructions rather than assuming all parties use the same table set.

Before balance payment or pickup

Freeze the AQL plan before the factory visit.

Send the lot details, approved specs, defect examples, proposed limits, and release deadline. Agent Huang will help scope the buyer-side inspection before goods leave supplier control.

Plan My AQL Inspection