· 5 min read
Garment Quality Control: AQL, Defect Types and Measurement Tolerances Explained
Garment quality control checks each production stage against an approved sample and a written spec. For large orders, a random sample is inspected using AQL tables — typically AQL 2.5 for major defects and 4.0 for minor ones. For small runs, every piece can be checked. This guide explains the stages, defect classes, AQL and tolerances.
In short
Garment quality control checks each production stage against an approved sample and a written spec. For large orders, a random sample is inspected using AQL tables — typically AQL 2.5 for major defects and 4.0 for minor ones. For small runs, every piece can be checked. This guide explains the stages, defect classes, AQL and tolerances.
The short answer: garment quality control compares what is being made against two references — the approved pre-production sample and the written specification — at several points during production, not only at the end. On large orders, inspectors check a random sample of the finished goods and accept or reject the lot using AQL (acceptable quality limit) tables; the common apparel standard is zero critical defects, AQL 2.5 for major defects and AQL 4.0 for minor defects. On small runs of 25–150 pieces, it is practical to inspect every garment instead.
When is quality checked during production?
| Stage | What is checked |
|---|---|
| Incoming fabric and trims | Weight (GSM), shade, faults, shrinkage; zips, labels and thread against the spec |
| Cutting | Pattern, grain direction, shade matching between panels |
| In-line sewing | Stitch density, seam strength, symmetry, measurements on the first pieces of each size |
| Decoration | Print or embroidery position, colour, size and cure |
| Finishing | Loose threads trimmed, pressing, labels and trims attached correctly |
| Final inspection | Appearance, measurements, labelling, packing, carton contents |
Checking in-line matters because a problem found on the fifth piece costs minutes to fix, and the same problem found on the five-hundredth costs the order.
What is the difference between critical, major and minor defects?
| Class | Definition | Examples |
|---|---|---|
| Critical | Unsafe, or breaks a legal requirement | Broken needle left in a garment, sharp edges, wrong fibre content on the label |
| Major | A customer would be likely to return it or would not buy it | Hole, open seam, wrong size, obvious shade difference, misplaced or cracked print, broken zip |
| Minor | A departure from the standard that most customers would not notice or mind | A single untrimmed thread, a slight stitch irregularity on an inside seam |
Agree the classification before production. Whether a 5 mm logo misplacement is major or minor is a decision, and it should be yours.
What does AQL mean?
AQL stands for acceptable quality limit. It is a statistical sampling method, set out in the standard ISO 2859-1 (ANSI/ASQ Z1.4 in the United States), that answers a practical question: how many pieces must be inspected, and how many defects can be found, before the whole lot is rejected?
An AQL of 2.5 does not mean "2.5% of your order may be faulty and that is fine". It is the quality level at which a lot will usually pass inspection. A lower AQL number is stricter.
The usual settings for clothing are:
- Critical defects: none accepted
- Major defects: AQL 2.5
- Minor defects: AQL 4.0
How many pieces are inspected?
At the normal inspection level (general level II), the sample size depends on the lot size. The lot passes if the number of defects found is at or below the accept number.
| Order size (pieces) | Pieces inspected | Major defects (AQL 2.5): accept up to | Minor defects (AQL 4.0): accept up to |
|---|---|---|---|
| 151–280 | 32 | 2 | 3 |
| 281–500 | 50 | 3 | 5 |
| 501–1,200 | 80 | 5 | 7 |
| 1,201–3,200 | 125 | 7 | 10 |
So on a 400-piece order, 50 garments are picked at random from the packed cartons. If four of them have a major defect, the lot fails and is sorted and reworked before it can ship.
What about small orders?
Sampling statistics are designed for large lots. On a run of 25, 50 or 100 pieces, the sample sizes become so small that they say little, and it is realistic to look at every garment. For small orders, ask for 100% inspection: each piece checked for appearance and decoration, and measurements checked across each size.
What is a measurement tolerance?
Fabric stretches and hand-sewing varies, so no two garments are identical. A tolerance is the agreed range a measurement can fall within and still be acceptable.
| Measurement | Typical tolerance on knitwear |
|---|---|
| Chest width, body length | ±1 cm |
| Sleeve length | ±1 cm |
| Shoulder width | ±0.5–1 cm |
| Neck opening, cuff | ±0.5 cm |
| Print or embroidery position | ±0.5–1 cm |
Tolerances are usually tighter on woven garments and leather than on stretch knits. Put them in the tech pack or the written spec, next to the size chart.
What should you ask your manufacturer about quality control?
- At which stages do you inspect, and who does it?
- Is the final inspection 100% or sampled, and at what AQL?
- Will I receive photos during production and before shipping?
- What measurement tolerances do you work to?
- What happens if finished goods do not match the approved sample?
- Can I arrange an independent third-party inspection if I want one?
Clear answers to these are one of the best signs you are dealing with a serious factory. More questions are in how to find a clothing manufacturer.
What can you do as the buyer?
- Approve a physical sample and keep it. See sample types explained.
- Write the spec down: fabric weight, measurements, tolerances, decoration positions.
- Ask for photos of the first finished pieces before the whole run is completed.
- Inspect on arrival. Open the cartons promptly, count, check a spread of sizes and report anything within a few days.
Quality control at SeamFoundry
Every order is made against a pre-production sample you have approved. Production is inspected in-line at each stage — fabric relaxing and cutting, stitching and decoration — followed by a final piece-by-piece check before packing. Tell us your quality requirements in the quote form, or see how it works for the process from enquiry to delivery.
