AQL Sample Size for Lot 4,000 — GII Inspection at AQL 2.5
What this means
For a production lot of 4,000 garments at GII inspection level with an AQL of 2.5 (major (standard) defects), ISO 2859-1 requires the buyer's QC inspector to pull 200 garments at random from across the lot. If they find 10 or fewer defects, the entire lot is accepted. 11 or more defects means the lot is rejected — the factory must then sort 100% of the lot, repair defective pieces, and re-present for inspection.
Inspection level note: Default for garment buyer QC — most shipments inspected here.
AQL tier: Industry-standard major defect AQL — broken stitch, open seam, wrong measurement.
Accept / reject decision table
| Defects found in sample | Decision |
|---|---|
| 0 defects | ACCEPT |
| 1 defect | ACCEPT |
| 2 defects | ACCEPT |
| 3 defects | ACCEPT |
| 4 defects | ACCEPT |
| 5 defects | ACCEPT |
| 6 defects | ACCEPT |
| 7 defects | ACCEPT |
| 8 defects | ACCEPT |
| 9 defects | ACCEPT |
| 10 defects | ACCEPT |
| 11 defects | REJECT |
| 12 defects | REJECT |
Worked example — your shipment
Suppose your factory has produced 4,000 garments for a buyer who specified GII / AQL 2.5. The buyer's inspector arrives, opens 5-8 cartons at random, and pulls 200 garments across them.
If the inspector finds 10 defects in those 200 garments → lot ACCEPTED, container ships.
If the inspector finds 11 defects → lot REJECTED. You sort 100% of 4,000 pieces, repair, and re-present in 2-3 days.
How this combination compares
This is the GII / AQL 2.5 combination — the major (standard) sampling plan for GII inspection. If your buyer's PO sheet specified different parameters, here are the adjacent plans:
FAQ for Lot 4,000 · GII · AQL 2.5
What if I find exactly 10 defects?
10 defects = ACCEPT. The accept number is the maximum number of defects you can have in the sample without rejecting. Exactly at the limit is still acceptable.
What if I find 11 defects?
11 defects = REJECT. The reject number is the lowest defect count that fails the lot. There is no "borderline" — anything ≥ 11 triggers a reject.
Can I argue an inspection where I found 11 defects?
You cannot argue the math — the accept/reject thresholds come from the ISO 2859 statistical tables. What you can argue is the classification of each defect. If the inspector marked something as a Major defect that your buyer's spec sheet calls Minor, push back with the spec sheet in writing.
What's the underlying acceptance probability at AQL 2.5?
ISO 2859-1 plans are calibrated so that lots actually at the AQL value get accepted ~95% of the time. So a lot truly at 2.5% defect rate has a 95% chance of being accepted by this plan. Lots at 2× the AQL get rejected most of the time.
Use this in your own QC software
The same logic is published as a free MIT-licensed package:
$ npm install garment-aql-calculator $ pip install garment-aql-calculator // Node.js const { calculateAQL } = require('garment-aql-calculator'); calculateAQL({ lotSize: 4000, inspectionLevel: 'GII', aql: 2.5 }); // → { codeLetter: 'L', sampleSize: 200, acceptNumber: 10, rejectNumber: 11 }