Acceptable Quality Level (AQL) Explained — with the ISO 2859-1 Table
TL;DR: The Acceptable Quality Level is the maximum percentage of defective units that a batch may contain and still be accepted. AQL 2.5 means a lot is accepted when no more than 2.5% of units carry major defects.
AQL is defined in ISO 2859-1 (identical in practice to ANSI/ASQ Z1.4) and it determines both how many units an inspector samples and how many defects trigger a rejection.
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What Acceptable Quality Level actually means
Answer: AQL is not a quality target for the factory — it is the worst tolerable process average at which a lot will still usually be accepted. It exists because inspecting 100% of a 20,000-unit order is uneconomic.
AQL is not a quality target for the factory — it is the worst tolerable process average at which a lot will still usually be accepted. It exists because inspecting 100% of a 20,000-unit order is uneconomic. Instead, the inspector draws a statistically valid random sample and compares the defect count against published accept and reject numbers.
Expressed as a percentage: 0.65, 1.0, 1.5, 2.5, 4.0, 6.5
Applied separately to critical, major and minor defect classes
Standard consumer-goods setting: 0 critical / 2.5 major / 4.0 minor
Lower AQL = larger sample and stricter acceptance
How to read the ISO 2859-1 sample size table
Answer: Reading the table takes three steps. First, find your lot size row and take the code letter for General Inspection Level II.
Reading the table takes three steps. First, find your lot size row and take the code letter for General Inspection Level II. Second, look up the sample size for that letter. Third, read across to your AQL column for the accept (Ac) and reject (Re) numbers.
Lot 501–1,200 units → code letter J → sample 80 units
Lot 1,201–3,200 units → code letter K → sample 125 units
Lot 3,201–10,000 units → code letter L → sample 200 units
Lot 10,001–35,000 units → code letter M → sample 315 units
Lot 35,001–150,000 units → code letter N → sample 500 units
Which AQL should you use?
Answer: Match the AQL to the consequence of a defect reaching the end customer. Safety-critical and regulated categories use tighter limits; low-value cosmetic goods can tolerate looser ones.
Match the AQL to the consequence of a defect reaching the end customer. Safety-critical and regulated categories use tighter limits; low-value cosmetic goods can tolerate looser ones.
AQL 0.65 / 1.0 — toys, baby products, electricals, anything safety-regulated
AQL 1.5 / 2.5 — branded retail, premium apparel, department-store programmes
AQL 2.5 / 4.0 — general consumer goods, the global default
AQL 4.0 / 6.5 — promotional items, low-value commodity goods
Critical defects — always zero accepted, regardless of the major/minor AQL
Worked example: 5,000-unit order at AQL 2.5
A 5,000-unit lot falls in the 3,201–10,000 band, giving code letter L and a 200-unit random sample. At AQL 2.5 for major defects, the accept number is 10 and the reject number is 11. So if the inspector records 10 or fewer major defects across the 200 sampled units, the lot passes. At 11 or more it fails and you can hold payment, demand 100% sorting and rework, or refuse the shipment.
Common AQL mistakes importers make
Most disputes with suppliers come from an AQL that was never written into the purchase order.
Not stating the AQL and inspection level in the PO or contract
Letting the factory pick the sample — samples must be random across cartons
Using one AQL for all three defect classes
Treating AQL 2.5 as a target rather than an acceptance ceiling
Skipping the defect list — 'major' and 'minor' must be defined per product
Side-by-Side Comparison
| Lot size | Code letter (GIL II) | Sample size | AQL 2.5 accept / reject | AQL 4.0 accept / reject |
|---|---|---|---|---|
| 151–280 | G | 32 | 2 / 3 | 3 / 4 |
| 281–500 | H | 50 | 3 / 4 | 5 / 6 |
| 501–1,200 | J | 80 | 5 / 6 | 7 / 8 |
| 1,201–3,200 | K | 125 | 7 / 8 | 10 / 11 |
| 3,201–10,000 | L | 200 | 10 / 11 | 14 / 15 |
| 10,001–35,000 | M | 315 | 14 / 15 | 21 / 22 |
| 35,001–150,000 | N | 500 | 21 / 22 | 21 / 22 |
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Frequently Asked Questions
What does AQL 2.5 mean?
AQL 2.5 means the inspection accepts a lot when no more than 2.5% of the sampled units carry major defects. For a 200-unit sample the accept number is 10 major defects and the reject number is 11.
What is the acceptable quality level standard?
ISO 2859-1, published in the United States as ANSI/ASQ Z1.4. It defines lot-size code letters, inspection levels, sample sizes and accept/reject numbers for each AQL value.
How is AQL sample size calculated?
Take your lot size, read the code letter for General Inspection Level II from the ISO 2859-1 table, then read the sample size for that letter. A 5,000-unit lot gives code letter L and a 200-unit sample.
What is the difference between AQL 1.0 and AQL 2.5?
AQL 1.0 tolerates 1% defectives and rejects at a lower defect count for the same sample size, so it is stricter and used for safety-regulated goods. AQL 2.5 is the general consumer-goods default.
Can critical defects be accepted under AQL?
No. Critical defects — those creating a safety hazard or breaching a legal requirement — carry a zero accept number in virtually all inspection protocols, no matter which AQL applies to major and minor defects.
How do I get started with Small World India?
Send us your product specs or reference images via the contact form. Within 48 hours we shortlist 3 vetted factories with FOB pricing, MOQ, and lead times — at no cost.
What is the typical MOQ for sourcing from India?
MOQs range from 100 units (jewelry, handicrafts) to 5,000+ units (textiles, packaging). We negotiate flexible MOQs for first orders and combine SKUs across factories when needed.
How does Small World India ensure product quality?
Every order includes factory audit, mid-production inspection, and pre-shipment AQL 2.5 inspection by our in-house QC team. You receive photos, videos, and a full inspection report before shipment leaves the port.
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