AQL Inspection China
Understand AQL inspection China: sampling tables, defect limits, and sample sizes for your shipment.
AQL (Acceptable Quality Limit) is the statistical sampling standard used for most China pre-shipment inspections. Instead of checking every unit, a representative sample is inspected based on ANSI ASQ Z1.4 (formerly MIL-STD-105E). Understanding AQL tables, defect classifications, and sample sizes helps you set clear quality expectations with your supplier.
What is AQL in pre-shipment inspection?
AQL defines the maximum number of defective units allowed in a sample for the batch to pass inspection. An AQL of 2.5 means up to 2.5% defective units are acceptable in the sampled population — not that 2.5% of your entire order is allowed to be defective.
Instead of a 100% inspection (impractical for large shipments), a random sample is drawn. If defects in the sample stay below the AQL limit, the batch passes. If they exceed the limit, the batch is rejected and rework is required.
Originally developed as MIL-STD-105E, ANSI ASQ Z1.4 is the industry-standard sampling procedure used by third-party inspection companies in China. It defines sample sizes, acceptance numbers (Ac), and rejection numbers (Re) for each AQL level.
Inspectors classify defects as critical, major, or minor. Each defect class uses a different AQL limit — for example, AQL 0 for critical, AQL 2.5 for major, and AQL 4.0 for minor defects.
AQL tables and ANSI ASQ Z1.4 standards explained
AQL inspection follows a three-step process using standard tables:
- Step 1: Determine inspection level — Most China inspections use Level II (normal) as the default. Level I (reduced) is used for proven suppliers. Level III (tightened) is used for critical or new products. Special levels (S-1 through S-4) are used for very small sample sizes such as destructive testing.
- Step 2: Find the sample size code letter — Using the batch size (total units in the order) and the inspection level, the ANSI ASQ Z1.4 table gives a code letter (A through R). A larger batch size results in a later code letter and a larger sample.
- Step 3: Look up sample size and accept/reject numbers — The code letter maps to a specific sample size and to the acceptance (Ac) and rejection (Re) numbers for each AQL level. For example, a batch of 3,200 units at Level II yields code letter M, a sample of 315 units, and at AQL 2.5 the accept/reject numbers are Ac=14, Re=15.
This sounds complex, but our AQL calculator handles it automatically. Enter your batch size and AQL level to get instant sample size and pass/fail limits.
AQL 2.5 vs 4.0: Choosing the right level
Selecting the correct AQL level for each defect class is critical for setting realistic quality expectations:
- AQL 0 (Zero defect) — Used for critical defects involving safety, regulatory compliance, or legal issues. Any single critical defect in the sample triggers 100% inspection of the batch. Examples: electrical safety failure, lead content exceedance, missing FDA registration mark.
- AQL 2.5 — The most common level for major defects. Accepts up to 2.5% defective units in the sample. Used for functional issues, missing parts, incorrect dimensions, wrong color, or workmanship that affects product use. Most consumer goods inspections default to AQL 2.5 for major defects.
- AQL 4.0 — Used for minor defects that do not affect function or safety but detract from appearance or presentation. Examples: small scratches, slight color variation within tolerance, uneven stitching on a hidden seam, minor packaging scuffs.
- AQL 6.5 — Occasionally used for very minor cosmetic issues where high perfection is not required. Rarely used for consumer goods exports; most importers prefer AQL 4.0 as the maximum acceptable level.
How many samples do you need?
The sample size depends entirely on your batch size and the selected inspection level. Here are common reference points under normal Level II:
- Batch of 500 units — Sample size is 50 units (code letter H). At AQL 2.5: accept ≤3 defects, reject at 4.
- Batch of 1,500 units — Sample size is 125 units (code letter K). At AQL 2.5: accept ≤7 defects, reject at 8.
- Batch of 3,200 units — Sample size is 200 units (code letter L). Wait — actually code letter M gives 315 units, L gives 200. For 3,201-10,000 at Level II, code letter M = 315 sample. At AQL 2.5: accept ≤14 defects, reject at 15.
- Batch of 50,000 units — Sample size is 500 units (code letter N). At AQL 2.5: accept ≤21 defects, reject at 22.
Use our AQL calculator to determine the exact sample size for your shipment batch. It supports batch sizes from 2 to 500,000+ and all standard AQL levels.
Critical, major, and minor defect classification
Proper defect classification is essential because each class uses a different AQL limit. CloudSpects inspectors follow industry-standard classification criteria:
- Critical defects — Render the product unsafe, illegal, or unfit for use. Includes regulatory non-compliance (FDA, CE, RoHS), safety hazards (sharp edges, toxic materials, fire risk), and incorrect product that would trigger a recall. AQL: 0. One critical defect = batch rejected.
- Major defects — Materially affect the product's function, appearance, or durability. Includes broken parts, incorrect dimensions, wrong color, missing components, function failure, poor workmanship, packaging that exposes product to damage. AQL: 2.5 (typical).
- Minor defects — Do not affect function or safety but fall short of the agreed standard. Includes small scratches on non-visible surfaces, slightly irregular stitching, minor color variance within reasonable tolerance, packaging creases that don't affect protection. AQL: 4.0 (typical).
Your inspection contract can specify alternative defect classifications for your specific product. We work with you to define the quality standards before the inspector visits.
Book a pre-shipment inspection with AQL sampling
CloudSpects applies ANSI ASQ Z1.4 AQL sampling across all our pre-shipment inspection China services. Pricing starts from $169 per man-day. Use our AQL calculator first to determine your sample size, then book the inspection.
Frequently asked questions
What is AQL 2.5 in China inspection?
AQL 2.5 means up to 2.5% defective units are allowed in the sample for the batch to pass inspection for major defects. In practice, for a sample of 200 units, AQL 2.5 allows up to 7 major defects (accept number = 7). If 8 or more major defects are found, the batch is rejected. It does NOT mean 2.5% of your total order can be defective — the limit applies to the sample, and rejection triggers corrective action on the whole batch.
Can I change the AQL level for my inspection?
Yes. AQL levels are agreed between the buyer and the inspection company before the visit. If your product has stricter requirements (e.g., electronics, medical devices, baby products), you can specify AQL 1.0, 1.5, or even AQL 0.65 for major defects. We recommend discussing AQL levels with your CloudSpects account manager during booking.
What happens if my shipment fails the AQL inspection?
If defects exceed the accept number (Re number reached), the batch is marked as failed. Options include: sorting (100% inspection to remove defects), rework by the factory (with a re-inspection), discounted acceptance, or rejection with replacement order. CloudSpects provides detailed photos and defect descriptions to support your decision. Read our guide: what happens when pre-shipment inspection fails.
Do I need to know AQL to book an inspection?
No. CloudSpects handles AQL sampling as part of every standard PSI booking. If you don't specify an AQL level, we default to the widely used standard: AQL 0 for critical, AQL 2.5 for major, and AQL 4.0 for minor defects. Our inspectors are trained in ANSI ASQ Z1.4 and apply the correct sample size for your batch automatically.