AQL in one paragraph
This page is the short definition. For the full code-letter and sampling tables, inspection levels and a worked furniture example, read AQL sampling explained; to get a sample size and accept and reject numbers for your own lot, use the AQL calculator. The term comes from ISO 2859-1, now in its 2026 edition, and is used the same way in ANSI/ASQ Z1.4.
What the AQL number controls
A sampling plan has three inputs. The lot size and the inspection level give a code letter, and the code letter gives the sample size. The AQL is the third input. It picks the column in the sampling table that holds the accept and reject numbers.
Each defect class gets its own AQL. A common setting is 0 for critical, 2.5 for major and 4.0 for minor defects. A lower number is stricter: fewer defects are allowed in the same sample.
Worked example: 2,000 cushion covers
A buyer orders 2,000 printed cushion covers and inspects at general level II. The lot falls in the 1,201 to 3,200 range, which gives code letter K and a sample of 125 covers. The AQL then sets the limits:
| Class | AQL | Accept | Reject |
|---|---|---|---|
| Critical | 0 | 0 | 1 |
| Major | 2.5 | 7 | 8 |
| Minor | 4.0 | 10 | 11 |
If the buyer tightens major defects to AQL 1.5, the sample stays at 125 but the major limit drops to accept 5, reject 6. Changing the AQL moves the limits, not the sample. Try other settings in the AQL calculator.
What AQL does not promise
AQL 2.5 does not mean a 2.5% defect rate is allowed in the shipment, and an accepted lot is not defect-free. The plan only judges the sample. Defects found in the sample still need repair or replacement. Lab tests, packing and documents sit outside the AQL count and are checked on their own terms. The full tables and the arrow rule for small lots are in AQL sampling explained.
How Clear To Load uses AQL
We agree the AQL for each defect class with you before the visit and write it into the checklist. Unless you choose otherwise, we use general level II with 0 / 2.5 / 4.0. The inspector draws the sample at random from packed cartons, counts defects by class and compares each count with its limits. The result feeds the verdict on every pre-shipment inspection.