Free tools/Production & IE
AQL Sampling Calculator (ISO 2859-1 / ANSI Z1.4)
Find the AQL sample size and accept/reject numbers for a garment inspection from lot size, inspection level and AQL. Single sampling, normal inspection, with the full Level II table for AQL 1.5, 2.5 and 4.0.
Sample size
125pcs
Accept (Ac)
7
Reject (Re)
8
The formula
Lot size and inspection level give a code letter (Table I). The code letter and AQL give the sample size and the accept/reject numbers (Table II-A, single sampling, normal inspection). An arrow in the table means use the first row below or above it that has numbers, with that row's sample size.
Worked example
Lot size: 3000 pcs, Inspection level: Level II (normal), AQL: 2.5. Result: Sample size = 125 pcs; Accept (Ac) = 7; Reject (Re) = 8.
What AQL means in a garment final inspection
AQL (acceptance quality limit) is the worst defect rate, in percent, that the buyer is willing to accept as a process average. It does not mean 2.5% of the shipment may be defective; it sets how many defective pieces in a random sample are enough to reject the lot.
The inspector takes the sample size the table gives, checks every piece, and counts defective pieces. If the count is at or below Ac, the lot passes. If it reaches Re, the lot fails.
Many buyers inspect major and minor defects against different AQLs, for example 2.5 for major and 4.0 for minor, and allow zero critical defects (anything unsafe, such as a needle fragment or a sharp edge). These are common buyer practices, not a universal rule; the buyer's quality manual decides.
General inspection Level II is the normal default. Level I takes a smaller sample when the buyer accepts less discrimination; Level III takes a larger one for higher-risk orders.
AQL sampling table: Level II, normal inspection
| Lot size | Code letter | AQL 1.5 (n, Ac/Re) | AQL 2.5 (n, Ac/Re) | AQL 4.0 (n, Ac/Re) |
|---|---|---|---|---|
| 2 to 8 | A | 8, 0/1 | 5, 0/1 | 3, 0/1 |
| 9 to 15 | B | 8, 0/1 | 5, 0/1 | 3, 0/1 |
| 16 to 25 | C | 8, 0/1 | 5, 0/1 | 3, 0/1 |
| 26 to 50 | D | 8, 0/1 | 5, 0/1 | 13, 1/2 |
| 51 to 90 | E | 8, 0/1 | 20, 1/2 | 13, 1/2 |
| 91 to 150 | F | 32, 1/2 | 20, 1/2 | 20, 2/3 |
| 151 to 280 | G | 32, 1/2 | 32, 2/3 | 32, 3/4 |
| 281 to 500 | H | 50, 2/3 | 50, 3/4 | 50, 5/6 |
| 501 to 1,200 | J | 80, 3/4 | 80, 5/6 | 80, 7/8 |
| 1,201 to 3,200 | K | 125, 5/6 | 125, 7/8 | 125, 10/11 |
| 3,201 to 10,000 | L | 200, 7/8 | 200, 10/11 | 200, 14/15 |
| 10,001 to 35,000 | M | 315, 10/11 | 315, 14/15 | 315, 21/22 |
| 35,001 to 150,000 | N | 500, 14/15 | 500, 21/22 | 315, 21/22 |
| 150,001 to 500,000 | P | 800, 21/22 | 500, 21/22 | 315, 21/22 |
| 500,001 and over | Q | 800, 21/22 | 500, 21/22 | 315, 21/22 |
Sample size and accept/reject numbers (n, Ac/Re) by lot size at general inspection Level II for AQL 1.5, 2.5 and 4.0, from ISO 2859-1 Tables I and II-A. When n is larger than the lot, inspect every piece.
Assumptions
- Single sampling plan, normal inspection. Tightened and reduced inspection use different tables.
- When the table sample size is equal to or larger than the lot, the sample is the whole lot (100% inspection) with the same accept and reject numbers.
- Accept and reject numbers count defective pieces found in the sample, checked separately for each AQL you inspect against.
Questions
- What is AQL 2.5?
- An acceptance quality limit of 2.5%. For a lot of 3,000 pieces at Level II, you inspect 125 pieces and accept the lot with 7 or fewer defective pieces; 8 or more rejects it.
- How is the AQL sample size chosen?
- From the lot size and inspection level, which give a code letter (Level II: 1,201 to 3,200 pieces is K), and the code letter gives the sample size (K is 125). For some AQLs the table points to a neighbouring letter, and then that letter's sample size is used.
- What happens when a lot fails AQL inspection?
- The lot is rejected as presented. Usually the factory sorts the whole lot, repairs or removes the defective pieces, and offers it for re-inspection. The buyer decides whether re-inspection is allowed and at what level.
- Do critical defects use an AQL?
- Most buyers accept zero critical defects: one unsafe piece fails the lot regardless of the major and minor counts.
Read the guide
In the platform
Intelactory ties every inspection result to the lot that produced it, so a failed audit traces back to its dye batch and line.